644704632 has 96 divisors (see below), whose sum is σ = 2051365680. Its totient is φ = 180334080.

The previous prime is 644704591. The next prime is 644704649. The reversal of 644704632 is 236407446.

644704632 is a `hidden beast` number, since 644 + 7 + 0 + 4 + 6 + 3 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21013 + ... + 41604.

Almost surely, 2^644704632 is an apocalyptic number.

It is an amenable number.

644704632 is an abundant number, since it is smaller than the sum of its proper divisors (1406661048).

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

644704632 is a wasteful number, since it uses less digits than its factorization.

644704632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62653 (or 62646 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 36.

The square root of 644704632 is about 25391.0344806981. The cubic root of 644704632 is about 863.8803525162.

The spelling of 644704632 in words is "six hundred forty-four million, seven hundred four thousand, six hundred thirty-two".