656989768 has 8 divisors (see below), whose sum is σ = 1231855830. Its totient is φ = 328494880.

The previous prime is 656989763. The next prime is 656989783. The reversal of 656989768 is 867989656.

It can be written as a sum of positive squares in only one way, i.e., 462164004 + 194825764 = 21498^2 + 13958^2 .

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

It is not an unprimeable number, because it can be changed into a prime (656989763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41061853 + ... + 41061868.

Almost surely, 2^656989768 is an apocalyptic number.

It is an amenable number.

656989768 is a deficient number, since it is larger than the sum of its proper divisors (574866062).

656989768 is a wasteful number, since it uses less digits than its factorization.

656989768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82123727 (or 82123723 counting only the distinct ones).

The product of its digits is 39191040, while the sum is 64.

The square root of 656989768 is about 25631.8116410058. The cubic root of 656989768 is about 869.3330723514. Note that the first 3 decimals are identical.

It can be divided in two parts, 65698 and 9768, that added together give a triangular number (75466 = T₃₈₈).

The spelling of 656989768 in words is "six hundred fifty-six million, nine hundred eighty-nine thousand, seven hundred sixty-eight".