**Gematripedia Database: 666**

666 (six hundred [and] sixty-six) is the natural number following 665 and preceding 667.

666 is called the “Number of the Beast” in (most manuscripts of) chapter 13 of the Book of Revelation, of the New Testament, and also in popular culture, for example the British heavy metal band Iron Maiden’s third studio album The Number of the Beast and its title track.

666 is the sum of the first 36 natural numbers ({\displaystyle \sum _{i=1}^{36}i}{\displaystyle \sum _{i=1}^{36}i}, i.e. 1 + 2 + 3 + … + 34 + 35 + 36 = 666), and thus it is a triangular number. Because 36 is also triangular, 666 is a doubly triangular number. Also, 36 = 15 + 21; 15 and 21 are also triangular numbers, and 152 + 212 = 225 + 441 = 666.

In base 10, 666 is a repdigit (and therefore a palindromic number) and a Smith number. A prime reciprocal magic square based on 1/149 in base 10 has a magic total of 666.

The prime factorization of 666 is 2 • 32 • 37. Also, 666 is the sum of the squares of the first seven primes.

The Roman numeral for 666, DCLXVI, has exactly one occurrence of all symbols whose value is less than 1000 in decreasing order (D = 500, C = 100, L = 50, X = 10, V = 5, I = 1).

In the Textus Receptus manuscripts of the New Testament, the Book of Revelation (13:17–18) cryptically asserts 666 to be “man’s number” or “the number of a man” (depending on how the text is translated) associated with the Beast, an antagonistic creature that appears briefly about two-thirds into the apocalyptic vision. Some manuscripts of the original Greek use the symbols χξϛ chi xi stigma (or χξϝ with a digamma), while other manuscripts spell out the number in words.

In modern popular culture, 666 has become one of the most widely recognized symbols for the Antichrist or, alternatively, the devil. The number 666 is purportedly used to invoke Satan. Earnest references to the number occur both among apocalypticist Christian groups and in explicitly anti-Christian subcultures. References in contemporary Western art or literature are, more likely than not, intentional references to the Beast symbolism. Such popular references are therefore too numerous to list.

It is common to see the symbolic role of the integer 666 transferred to the digit sequence 6-6-6. Some people take the Satanic associations of 666 so seriously that they actively avoid things related to 666 or the digits 6-6-6. This is known as hexakosioihexekontahexaphobia.

The Number of the Beast is cited as 616 in some early biblical manuscripts, the earliest known instance being in Papyrus 115.