666 (number) facts for kids
666 is a natural number after 665 and before 667. It is a number with many properties. One of these properties is that it is the sum of the first 36 natural numbers. That makes 666 a triangular number. 666 is the sum of the first 144 decimals (digits after the decimal point) of pi. The bible says that the number 666 is associated with the devil.
666 (number) Facts for Kids. Kiddle Encyclopedia.