644535264 has 48 divisors (see below), whose sum is σ = 1737641808. Its totient is φ = 209037312.

The previous prime is 644535257. The next prime is 644535277. The reversal of 644535264 is 462535446.

644535264 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (48).

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, 87177 + ... + 94280.

It is an arithmetic number, because the mean of its divisors is an integer number (36200871).

Almost surely, 2^644535264 is an apocalyptic number.

It is an amenable number.

644535264 is an abundant number, since it is smaller than the sum of its proper divisors (1093106544).

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

644535264 is a wasteful number, since it uses less digits than its factorization.

644535264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181507 (or 181499 counting only the distinct ones).

The product of its digits is 345600, while the sum is 39.

The square root of 644535264 is about 25387.6990686435. The cubic root of 644535264 is about 863.8046969397.

The spelling of 644535264 in words is "six hundred forty-four million, five hundred thirty-five thousand, two hundred sixty-four".