639587664 has 60 divisors (see below), whose sum is σ = 1856263136. Its totient is φ = 213194592.

The previous prime is 639587653. The next prime is 639587677. The reversal of 639587664 is 466785936.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 639587664.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78364 + ... + 86139.

Almost surely, 2^639587664 is an apocalyptic number.

It is an amenable number.

639587664 is an abundant number, since it is smaller than the sum of its proper divisors (1216675472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639587664 is a wasteful number, since it uses less digits than its factorization.

639587664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164526 (or 164508 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The square root of 639587664 is about 25290.0704625353. The cubic root of 639587664 is about 861.5887631312.

The spelling of 639587664 in words is "six hundred thirty-nine million, five hundred eighty-seven thousand, six hundred sixty-four".