668881256 has 8 divisors (see below), whose sum is σ = 1254152370. Its totient is φ = 334440624.

The previous prime is 668881249. The next prime is 668881267. The reversal of 668881256 is 652188866.

It can be written as a sum of positive squares in only one way, i.e., 628304356 + 40576900 = 25066^2 + 6370^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41805071 + ... + 41805086.

Almost surely, 2^668881256 is an apocalyptic number.

It is an amenable number.

668881256 is a deficient number, since it is larger than the sum of its proper divisors (585271114).

668881256 is a wasteful number, since it uses less digits than its factorization.

668881256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83610163 (or 83610159 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 50.

The square root of 668881256 is about 25862.7387567520. The cubic root of 668881256 is about 874.5467065998.

The spelling of 668881256 in words is "six hundred sixty-eight million, eight hundred eighty-one thousand, two hundred fifty-six".