6640865688 has 32 divisors (see below), whose sum is σ = 16604179200. Its totient is φ = 2213353248.

The previous prime is 6640865629. The next prime is 6640865713. The reversal of 6640865688 is 8865680466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338533 + ... + 357611.

It is an arithmetic number, because the mean of its divisors is an integer number (518880600).

Almost surely, 2^6640865688 is an apocalyptic number.

It is an amenable number.

6640865688 is an abundant number, since it is smaller than the sum of its proper divisors (9963313512).

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

6640865688 is a wasteful number, since it uses less digits than its factorization.

6640865688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33591 (or 33587 counting only the distinct ones).

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

The square root of 6640865688 is about 81491.5068458057. The cubic root of 6640865688 is about 1879.6409537659.

The spelling of 6640865688 in words is "six billion, six hundred forty million, eight hundred sixty-five thousand, six hundred eighty-eight".