639810676 has 24 divisors (see below), whose sum is σ = 1135821960. Its totient is φ = 315313152.

The previous prime is 639810637. The next prime is 639810679. The reversal of 639810676 is 676018936.

It can be written as a sum of positive squares in 4 ways, for example, as 132480100 + 507330576 = 11510^2 + 22524^2 .

It is a super-2 number, since 2×639810676² = 818715402247153952, which contains 22 as substring.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639810679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 117306 + ... + 122638.

It is an arithmetic number, because the mean of its divisors is an integer number (47325915).

Almost surely, 2^639810676 is an apocalyptic number.

It is an amenable number.

639810676 is a deficient number, since it is larger than the sum of its proper divisors (496011284).

639810676 is a wasteful number, since it uses less digits than its factorization.

639810676 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5763 (or 5761 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 639810676 is about 25294.4791604808. The cubic root of 639810676 is about 861.6888913419.

The spelling of 639810676 in words is "six hundred thirty-nine million, eight hundred ten thousand, six hundred seventy-six".