643585656 has 32 divisors (see below), whose sum is σ = 1838816640. Its totient is φ = 183881568.

The previous prime is 643585639. The next prime is 643585669. The reversal of 643585656 is 656585346.

643585656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 1915266 + ... + 1915601.

It is an arithmetic number, because the mean of its divisors is an integer number (57463020).

Almost surely, 2^643585656 is an apocalyptic number.

It is an amenable number.

643585656 is an abundant number, since it is smaller than the sum of its proper divisors (1195230984).

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

643585656 is a wasteful number, since it uses less digits than its factorization.

643585656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3830883 (or 3830879 counting only the distinct ones).

The product of its digits is 2592000, while the sum is 48.

The square root of 643585656 is about 25368.9900469057. The cubic root of 643585656 is about 863.3802676027.

The spelling of 643585656 in words is "six hundred forty-three million, five hundred eighty-five thousand, six hundred fifty-six".