The apocalypse number, 666, often referred to as the beast number, is referred to in the bible, Revelations 13:18.

While the actual meaning or relevance of the number remain unclear, the number itself has some surprisingly interesting characteristics.The sum of the first 36 positive numbers is 666 which makes it the 36th triangular number.The sum of the squares of the first seven prime numbers is 666.

Example:

1³+2³+4³+5³+6³+5³+4³+3³+2³+1³ = 666

6+6+6+6³+6³+6³ = 666

Multiplying the sides of the primitive right triangle 12-35-37 by 18 yields non-primitive sides of 216-630-666.

Even more surprising is the fact that these sides can be written in the Pythagorean Theorem form:

(6x6x6)²+(666-6×6)² = 666²