644596704 has 120 divisors (see below), whose sum is σ = 1903432608. Its totient is φ = 213995520.

The previous prime is 644596661. The next prime is 644596727. The reversal of 644596704 is 407695446.

644596704 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 644596704.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1116864 + ... + 1117440.

Almost surely, 2^644596704 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644596704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (951716304).

644596704 is an abundant number, since it is smaller than the sum of its proper divisors (1258835904).

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

644596704 is a wasteful number, since it uses less digits than its factorization.

644596704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1030 (or 1013 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 644596704 is about 25388.9090746334. The cubic root of 644596704 is about 863.8321433171.

The spelling of 644596704 in words is "six hundred forty-four million, five hundred ninety-six thousand, seven hundred four".