Selected numbers

• 40000 – round number
• 40320 – smallest factorial
  Factorial
  In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n...
  
   that is not a highly composite number
  Highly composite number
  A highly composite number is a positive integer with more divisors than any positive integer smaller than itself.The initial or smallest twenty-one highly composite numbers are listed in the table at right....
  
  
• 40425 – square pyramidal number
  Square pyramidal number
  In mathematics, a pyramid number, or square pyramidal number, is a figurate number that represents the number of stacked spheres in a pyramid with a square base...
  
  
• 40585 – largest factorion
  Factorion
  A factorion is a natural number that equals the sum of the factorials of its decimal digits. For example, 145 is a factorion because 1! + 4! + 5! = 1 + 24 + 120 = 145.There are just four factorions and they are 1, 2, 145 and 40585 .-Upper bound:...
  
  
• 40678 – pentagonal pyramidal number
  Pentagonal pyramidal number
  A pentagonal pyramidal number is a figurate number that represents the number of objects in a pyramid with a pentagonal base. The nth pentagonal pyramidal number is equal to the sum of the first n pentagonal numbers....
  
  
• 40804 – palindromic
  Palindromic number
  A palindromic number or numeral palindrome is a 'symmetrical' number like 16461, that remains the same when its digits are reversed. The term palindromic is derived from palindrome, which refers to a word like rotor that remains unchanged under reversal of its letters...
  
   square
• 41041 – Ryle number
• 41616 – triangular square number
• 41835 – Motzkin number
  Motzkin number
  In mathematics, a Motzkin number for a given number n is the number of different ways of drawing non-intersecting chords on a circle between n points. The Motzkin numbers have very diverse applications in geometry, combinatorics and number theory...
  
  
• 42680 – octahedral number
  Octahedral number
  In number theory, an octahedral number is a figurate number that represents the number of spheres in an octahedron formed from close-packed spheres...
  
  
• 42925 – square pyramidal number
  Square pyramidal number
  In mathematics, a pyramid number, or square pyramidal number, is a figurate number that represents the number of stacked spheres in a pyramid with a square base...
  
  
• 43261 – Markov number
  Markov number
  A Markov number or Markoff number is a positive integer x, y or z that is part of a solution to the Markov Diophantine equationx^2 + y^2 + z^2 = 3xyz,\,studied by .The first few Markov numbers are...
  
  
• 43560 – pentagonal pyramidal number
• 43691 – Wagstaff prime
• 44100 – sum of the cubes of the first 20 positive integers, sampling rate of Red Book
  Red Book
  Red Book, Redbooks, Little Red Book or Big Red Book may refer to:- Political or ideological pamphlets :* The Little Red Book, the name commonly known in the West for the pocket-size edition of Quotations from Chairman Mao Tse-Tung...
  
  -compliant audio compact disks
• 44721 – When n > 44721, the expression 1/n - 1/(n+2) drops down to fractions of a billionth. The corresponding sum in the Leibniz formula for pi is 0.785386986.
• 44944 – palindromic square
• 45360 – first number to have 100 factors (including one and itself)
• 46233 – sum of the first eight factorials
• 46368 – Fibonacci number
  Fibonacci number
  In mathematics, the Fibonacci numbers are the numbers in the following integer sequence:0,\;1,\;1,\;2,\;3,\;5,\;8,\;13,\;21,\;34,\;55,\;89,\;144,\; \ldots\; ....
  
  
• 46656 –
• 46657 – Carmichael number
• 46664
  46664 (number)
  46664 is a series of AIDS charity concerts played in honour of Nelson Mandela by South African musicians in the 2000s.-Origin:Mandela was imprisoned on Robben Island in 1964, and was the 466th prisoner to arrive that year...
  
  – Nelson Mandela
  Nelson Mandela
  Nelson Rolihlahla Mandela served as President of South Africa from 1994 to 1999, and was the first South African president to be elected in a fully representative democratic election. Before his presidency, Mandela was an anti-apartheid activist, and the leader of Umkhonto we Sizwe, the armed wing...
  
  's prisoner number
• 46853 – Number of customers in the SpongeBob SquarePants
  SpongeBob SquarePants
  SpongeBob SquarePants is an American animated television series, created by marine biologist and animator Stephen Hillenburg. Much of the series centers on the exploits and adventures of the title character and his various friends in the underwater city of "Bikini Bottom"...
  
   episode Patty Hype
• 47058 – primary pseudoperfect number
• 47806 – in hexadecimal
  Hexadecimal
  In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
  
   it is written as "BABE"
• 49151 – Woodall number
  Woodall number
  In number theory, a Woodall number is any natural number of the formfor some natural number n. The first few Woodall numbers are:Woodall numbers were first studied by Allan J. C. Cunningham and H. J. Woodall in 1917, inspired by James Cullen's earlier study of the similarly-defined Cullen numbers...
  
  
• 49726 – pentagonal pyramidal number