668556872 has 16 divisors (see below), whose sum is σ = 1254104700. Its totient is φ = 334128960.

The previous prime is 668556871. The next prime is 668556913. The reversal of 668556872 is 278655866.

It can be written as a sum of positive squares in 2 ways, for example, as 660181636 + 8375236 = 25694^2 + 2894^2 .

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (668556871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1622 + ... + 36602.

Almost surely, 2^668556872 is an apocalyptic number.

It is an amenable number.

668556872 is a deficient number, since it is larger than the sum of its proper divisors (585547828).

668556872 is a wasteful number, since it uses less digits than its factorization.

668556872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37376 (or 37372 counting only the distinct ones).

The product of its digits is 4838400, while the sum is 53.

The square root of 668556872 is about 25856.4667346488. The cubic root of 668556872 is about 874.4053088911.

The spelling of 668556872 in words is "six hundred sixty-eight million, five hundred fifty-six thousand, eight hundred seventy-two".