The Number of the Beast is a term in the Book of Revelation

Book of Revelation

The Book of Revelation is the final book of the New Testament. The title came into usage from the first word of the book in Koine Greek: apokalupsis, meaning "unveiling" or "revelation"...

, of the New Testament

New Testament

The New Testament is the second major division of the Christian biblical canon, the first such division being the much longer Old Testament....

, that is associated with the first Beast of Revelation chapter 13, the Beast of the sea. In most manuscripts of the New Testament and in English translations of the Bible

English translations of the Bible

The efforts of translating the Bible from its original languages into over 2,000 others have spanned more than two millennia. Partial translations of the Bible into languages of the English people can be traced back to the end of the 7th century, including translations into Old English and Middle...

, the number of the Beast is . In critical editions of the Greek text

Textual criticism

Textual criticism is a branch of literary criticism that is concerned with the identification and removal of transcription errors in the texts of manuscripts...

, such as the Novum Testamentum Graece

Novum Testamentum Graece

Novum Testamentum Graece is the Latin name editions of the original Greek-language version of the New Testament.The first printed edition was the Complutensian Polyglot Bible by Cardinal Francisco Jiménez de Cisneros, printed in 1514, but not published until 1520...

, it is noted that is a variant.
The Number of the Beast is described in the passage of Revelation 13:15–18 and the actual number is only mentioned once, in verse 18.