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25 (number)
Encyclopedia
25 is the natural number
following 24
and preceding 26
.
, being 5² = 5 × 5. It is the smallest square that is also a sum of two (non-zero) squares: 25 = 3² + 4². Hence it often appears in illustrations of the Pythagorean theorem
.
25 is a centered octagonal number
and an automorphic number
.
25 per cent means one quarter.
25 has an aliquot sum of 6 and number 6 is the first (or smallest) number to have an aliquot sequence
that does not culminate in 0 through a prime
. Twenty-five is the aliquot sum of three integers; 95, 119, and 143. Twenty-five is the second composite member of the 6-aliquot tree.
It is the smallest base 10 Friedman number
as it can be expressed by its own numbers: 5².
It is also a Cullen number
. 25 is the smallest pseudoprime
satisfying the congruence 7n = 7 mod n.
25 is the smallest aspiring number — a composite non-sociable number
whose aliquot sequence
does not terminate.
According to the Shapiro inequality
25 is the least odd integer n such that there exist
such that
where
.
Within base 10 one can readily test for divisibility by 25 by seeing if the last two digits of the number match 25, 50, 75 or 00.
25 and 49 are the only perfect squares in the following list:
13,25,37,49,511,613,715,817,919,1021,1123,1225,1327,1429...etc.
The formula in this list can be described as
where n clearly depends on the number of digits in Z and in 2Z+1.
In bases 30, 25 is a 1-automorphic number
(displayed as the numeral 'P' or 'R' dependant on the chossen digit set), and in base 10 a 2-automorphic number.
"Surrounding the throne were twenty-four other thrones, and seated on them were twenty-four elders. They were dressed in white and had crowns of gold on their heads." Which means that there were 25 thrones.
Twenty five is:
Natural number
In mathematics, the natural numbers are the ordinary whole numbers used for counting and ordering . These purposes are related to the linguistic notions of cardinal and ordinal numbers, respectively...
following 24
24 (number)
24 is the natural number following 23 and preceding 25.The SI prefix for 1024 is yotta , and for 10−24 yocto...
and preceding 26
26 (number)
26 is the natural number following 25 and preceding 27.- In mathematics :26 is the only positive integer that is one greater than a square and one less than a cube .A rhombicuboctahedron has twenty-six sides....
.
In mathematics
It is a square numberSquare number
In mathematics, a square number, sometimes also called a perfect square, is an integer that is the square of an integer; in other words, it is the product of some integer with itself...
, being 5² = 5 × 5. It is the smallest square that is also a sum of two (non-zero) squares: 25 = 3² + 4². Hence it often appears in illustrations of the Pythagorean theorem
Pythagorean theorem
In mathematics, the Pythagorean theorem or Pythagoras' theorem is a relation in Euclidean geometry among the three sides of a right triangle...
.
25 is a centered octagonal number
Centered octagonal number
A centered octagonal number is a centered figurate number that represents an octagon with a dot in the center and all other dots surrounding the center dot in successive octagonal layers...
and an automorphic number
Automorphic number
In mathematics an automorphic number is a number whose square "ends" in the same digits as number itself. For example, 52 = 25, 762 = 5776, and 8906252 = 793212890625, so 5, 76 and 890625 are all automorphic numbers.The sequence of automorphic numbers begins 1, 5, 6, 25, 76, 376, 625, 9376, .....
.
25 per cent means one quarter.
25 has an aliquot sum of 6 and number 6 is the first (or smallest) number to have an aliquot sequence
Aliquot sequence
In mathematics, an aliquot sequence is a recursive sequence in which each term is the sum of the proper divisors of the previous term. The aliquot sequence starting with a positive integer k can be defined formally in terms of the sum-of-divisors function σ1 in the following way:For example, the...
that does not culminate in 0 through a prime
Prime number
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example 5 is prime, as only 1 and 5 divide it, whereas 6 is composite, since it has the divisors 2...
. Twenty-five is the aliquot sum of three integers; 95, 119, and 143. Twenty-five is the second composite member of the 6-aliquot tree.
It is the smallest base 10 Friedman number
Friedman number
A Friedman number is an integer which, in a given base, is the result of an expression using all its own digits in combination with any of the four basic arithmetic operators and sometimes exponentiation. For example, 347 is a Friedman number since 347 = 73 + 4...
as it can be expressed by its own numbers: 5².
It is also a Cullen number
Cullen number
In mathematics, a Cullen number is a natural number of the form n · 2n + 1 . Cullen numbers were first studied by Fr. James Cullen in 1905...
. 25 is the smallest pseudoprime
Pseudoprime
In number theory, the Fermat pseudoprimes make up the most important class of pseudoprimes that come from Fermat's little theorem.- Definition :...
satisfying the congruence 7n = 7 mod n.
25 is the smallest aspiring number — a composite non-sociable number
Sociable number
Sociable numbers are generalizations of the concepts of amicable numbers and perfect numbers. A set of sociable numbers is a kind of aliquot sequence, or a sequence of numbers each of whose numbers is the sum of the factors of the preceding number, excluding the preceding number itself...
whose aliquot sequence
Aliquot sequence
In mathematics, an aliquot sequence is a recursive sequence in which each term is the sum of the proper divisors of the previous term. The aliquot sequence starting with a positive integer k can be defined formally in terms of the sum-of-divisors function σ1 in the following way:For example, the...
does not terminate.
According to the Shapiro inequality
Shapiro inequality
In mathematics, the Shapiro inequality is an inequality proposed by H. Shapiro in 1954.-Statement of the inequality:Suppose n is a natural number and x_1, x_2, \dots, x_n are positive numbers and:* n is even and less than or equal to 12, or...
25 is the least odd integer n such that there exist
such thatwhere
.Within base 10 one can readily test for divisibility by 25 by seeing if the last two digits of the number match 25, 50, 75 or 00.
25 and 49 are the only perfect squares in the following list:
13,25,37,49,511,613,715,817,919,1021,1123,1225,1327,1429...etc.
The formula in this list can be described as
where n clearly depends on the number of digits in Z and in 2Z+1.In bases 30, 25 is a 1-automorphic number
Automorphic number
In mathematics an automorphic number is a number whose square "ends" in the same digits as number itself. For example, 52 = 25, 762 = 5776, and 8906252 = 793212890625, so 5, 76 and 890625 are all automorphic numbers.The sequence of automorphic numbers begins 1, 5, 6, 25, 76, 376, 625, 9376, .....
(displayed as the numeral 'P' or 'R' dependant on the chossen digit set), and in base 10 a 2-automorphic number.
In religion
- In EzekielEzekielEzekiel , "God will strengthen" , is the central protagonist of the Book of Ezekiel in the Hebrew Bible. In Judaism, Christianity and Islam, Ezekiel is acknowledged as a Hebrew prophet...
's vision of a new temple: The number twenty-five is of cardinal importance in EzekielEzekielEzekiel , "God will strengthen" , is the central protagonist of the Book of Ezekiel in the Hebrew Bible. In Judaism, Christianity and Islam, Ezekiel is acknowledged as a Hebrew prophet...
's Temple Vision (in the Bible, EzekielEzekielEzekiel , "God will strengthen" , is the central protagonist of the Book of Ezekiel in the Hebrew Bible. In Judaism, Christianity and Islam, Ezekiel is acknowledged as a Hebrew prophet...
chapters 40-48).
- In The Book of Revelation's New International Version (©1984)
"Surrounding the throne were twenty-four other thrones, and seated on them were twenty-four elders. They were dressed in white and had crowns of gold on their heads." Which means that there were 25 thrones.
In sports
- The size of the full roster on a Major League BaseballMajor League BaseballMajor League Baseball is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League...
team for most of the season, except for regular-season games on or after September 1, when it expands to 40. - In baseball, the number 25 is typically reserved for the best slugger on the team. Examples include Mark McGwireMark McGwireMark David McGwire , nicknamed "Big Mac", is an American former professional baseball player who played his major league career with the Oakland Athletics and the St. Louis Cardinals. He is currently the hitting coach for the St...
, Barry BondsBarry BondsBarry Lamar Bonds is an American former Major League Baseball outfielder. Bonds played from 1986 to 2007, for the Pittsburgh Pirates and San Francisco Giants. He is the son of former major league All-Star Bobby Bonds...
, and Mark TeixeiraMark TeixeiraMark Charles Teixeira , nicknamed "Tex" is an American Major League Baseball player for the New York Yankees. Mostly a first baseman, he has also played third base and in the outfield...
. - The number of points needed to win a set in volleyball under rally scoring rules (except for the fifth set), so long as the losing team's score is two less than the winning team's score (i.e., if the winning team scores 25 points, the losing team can have no more than 23 points)
- In U.S. college footballCollege footballCollege football refers to American football played by teams of student athletes fielded by American universities, colleges, and military academies, or Canadian football played by teams of student athletes fielded by Canadian universities...
, schools that are members of NCAA Division I FBS are allowed to provide athletic scholarshipAthletic scholarshipAn athletic scholarship is a form of scholarship to attend a college or university awarded to an individual based predominantly on his or her ability to play in a sport...
s to a maximum of 25 new football players (i.e., players who were not previously receiving scholarships) each season.
In other fields
- The part of the name of LSD-25 molecule
- The number of years of marriage marked in a silver wedding anniversaryWedding anniversary-Official recognition:In the Commonwealth realms, one can receive a message from the monarch for 60th, 65th, and 70th wedding anniversaries, and any wedding anniversary after that...
. - The minimum age of candidates for election to the United States House of RepresentativesUnited States House of RepresentativesThe United States House of Representatives is one of the two Houses of the United States Congress, the bicameral legislature which also includes the Senate.The composition and powers of the House are established in Article One of the Constitution...
. "Under 25" provides a common cut-off point for designating youthYouthYouth is the time of life between childhood and adulthood . Definitions of the specific age range that constitutes youth vary. An individual's actual maturity may not correspond to their chronological age, as immature individuals could exist at all ages.-Usage:Around the world, the terms "youth",...
. - The number of cents in a quarterQuarter (United States coin)A quarter dollar, commonly shortened to quarter, is a coin worth ¼ of a United States dollar, or 25 cents. The quarter has been produced since 1796. The choice of 25¢ as a denomination, as opposed to 20¢ which is more common in other parts of the world, originated with the practice of dividing...
. - The usual TCPTransmission Control ProtocolThe Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
port for SMTP. - The designation of United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
Interstate 25Interstate 25Interstate 25 is an Interstate Highway in the western United States. It is primarily a north–south highway. I-25 stretches from Interstate 10 at Las Cruces, New Mexico, , to Interstate 90 in Buffalo, Wyoming, .Interstate 25 is the main north–south expressway through...
, a freeway that runs from New MexicoNew MexicoNew Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
to WyomingWyomingWyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High... - The designation of the M25M25 motorwayThe M25 motorway, or London Orbital, is a orbital motorway that almost encircles Greater London, England, in the United Kingdom. The motorway was first mooted early in the 20th century. A few sections, based on the now abandoned London Ringways plan, were constructed in the early 1970s and it ...
London Orbital motorway - Municipal Okrug 25, until March, 2010, name of Knyazhevo Municipal Okrug in Kirovsky District of Saint PetersburgSaint PetersburgSaint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
, Russia - The (critical) number of Florida electoral votes for the 2000 U.S. presidential election
- The name of the national board game of IndiaIndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
(PachisiPachisiPachisi is a cross and circle board game that originated in ancient India which has been described as the "national game of India". It is played on a board shaped like a symmetrical cross...
— Hindi for 25) - "25", a song by Veruca Salt from their 1994 album American ThighsAmerican ThighsAmerican Thighs is the first album by alternative rock band Veruca Salt. It was released through Minty Fresh Records on September 27, 1994, and re-released through DGC Records on November 8, 1994 . The title is a reference to a line from the AC/DC song "You Shook Me All Night Long"...
- "25th Floor", a song by Patti Smith Group from their 1978 album Easter
- "twentyfive", design studio in the Czech Republic
- Twenty FiveTwenty Five (album)Twenty Five is singer George Michael's 2006 greatest hits album, which celebrates the 25th anniversary of his music career. It was released on 13 November 2006 via Sony BMG...
is the name of a 2006 George MichaelGeorge MichaelGeorge Michael is a British musician, singer, songwriter and record producer who rose to fame in the 1980s when he formed the pop duo Wham! with his school friend, Andrew Ridgeley...
compilation celebrating 25 years in the music business (1981–2006) - "25 boy", in Cantonese Chinese, is a slang term meaning "traitor" as used in the Chinese movie Over the EdgeOver the Edge (film)Over the Edge is a drama film directed by Jonathan Kaplan released in 1979. Due to the negative publicity surrounding a wave of recent youth gang films, Over the Edge had a limited theatrical release in late 1979...
. - The per-second frame rate of the PALPALPAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
video standard - The number of the French department Doubs
- 25 random things about me, an Internet memeInternet memeThe term Internet meme is used to describe a concept that spreads via the Internet. The term is a reference to the concept of memes, although the latter concept refers to a much broader category of cultural information.-Description:...
utilizing Facebook's Notes feature