656688864 has 48 divisors (see below), whose sum is σ = 1856412432. Its totient is φ = 202057728.

The previous prime is 656688863. The next prime is 656688871. The reversal of 656688864 is 468886656.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×656688864² = 862480528203220992, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656688863) 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, 261849 + ... + 264344.

It is an arithmetic number, because the mean of its divisors is an integer number (38675259).

Almost surely, 2^656688864 is an apocalyptic number.

It is an amenable number.

656688864 is an abundant number, since it is smaller than the sum of its proper divisors (1199723568).

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

656688864 is a wasteful number, since it uses less digits than its factorization.

656688864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526219 (or 526211 counting only the distinct ones).

The product of its digits is 13271040, while the sum is 57.

The square root of 656688864 is about 25625.9412314943. The cubic root of 656688864 is about 869.2003327170.

The spelling of 656688864 in words is "six hundred fifty-six million, six hundred eighty-eight thousand, eight hundred sixty-four".