644209264 has 20 divisors (see below), whose sum is σ = 1288419520. Its totient is φ = 311713920.

The previous prime is 644209243. The next prime is 644209283. The reversal of 644209264 is 462902446.

644209264 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

644209264 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 648909 + ... + 649900.

It is an arithmetic number, because the mean of its divisors is an integer number (64420976).

Almost surely, 2^644209264 is an apocalyptic number.

It is an amenable number.

644209264 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

644209264 is a wasteful number, since it uses less digits than its factorization.

644209264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1298848 (or 1298842 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 37.

The square root of 644209264 is about 25381.2778244122. The cubic root of 644209264 is about 863.6590375593.

The spelling of 644209264 in words is "six hundred forty-four million, two hundred nine thousand, two hundred sixty-four".