656666656 has 12 divisors (see below), whose sum is σ = 1292812542. Its totient is φ = 328333312.

The previous prime is 656666603. The next prime is 656666669.

It is a happy number.

656666656 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 384944400 + 271722256 = 19620^2 + 16484^2 .

It is a super-2 number, since 2×656666656² = 862422194204444672, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10260385 + ... + 10260448.

Almost surely, 2^656666656 is an apocalyptic number.

It is an amenable number.

656666656 is a deficient number, since it is larger than the sum of its proper divisors (636145886).

656666656 is a wasteful number, since it uses less digits than its factorization.

656666656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20520843 (or 20520835 counting only the distinct ones).

The product of its digits is 6998400, while the sum is 52.

The square root of 656666656 is about 25625.5079169175. The cubic root of 656666656 is about 869.1905343586.

The spelling of 656666656 in words is "six hundred fifty-six million, six hundred sixty-six thousand, six hundred fifty-six".