668637504 has 70 divisors (see below), whose sum is σ = 1982066394. Its totient is φ = 222877440.

The previous prime is 668637491. The next prime is 668637511. The reversal of 668637504 is 405736866.

668637504 is a `hidden beast` number, since 6 + 6 + 8 + 637 + 5 + 0 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 668119104 + 518400 = 25848^2 + 720^2 .

It is a super-2 number, since 2×668637504² = 894152223510700032, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 668637504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 59307 + ... + 69674.

Almost surely, 2^668637504 is an apocalyptic number.

668637504 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

668637504 is an abundant number, since it is smaller than the sum of its proper divisors (1313428890).

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

668637504 is a wasteful number, since it uses less digits than its factorization.

668637504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129005 (or 128986 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 668637504 is about 25858.0259107303. The cubic root of 668637504 is about 874.4404603333.

The spelling of 668637504 in words is "six hundred sixty-eight million, six hundred thirty-seven thousand, five hundred four".