645706856 has 32 divisors (see below), whose sum is σ = 1235239200. Its totient is φ = 316345920.

The previous prime is 645706829. The next prime is 645706889. The reversal of 645706856 is 658607546.

645706856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 645706856.

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, 154166 + ... + 158298.

It is an arithmetic number, because the mean of its divisors is an integer number (38601225).

Almost surely, 2^645706856 is an apocalyptic number.

It is an amenable number.

645706856 is a deficient number, since it is larger than the sum of its proper divisors (589532344).

645706856 is a wasteful number, since it uses less digits than its factorization.

645706856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4529 (or 4525 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 47.

The square root of 645706856 is about 25410.7626017009. The cubic root of 645706856 is about 864.3277684456.

The spelling of 645706856 in words is "six hundred forty-five million, seven hundred six thousand, eight hundred fifty-six".