644325732 has 24 divisors (see below), whose sum is σ = 1670474400. Its totient is φ = 214775208.

The previous prime is 644325709. The next prime is 644325751. The reversal of 644325732 is 237523446.

644325732 is a `hidden beast` number, since 644 + 3 + 2 + 5 + 7 + 3 + 2 = 666.

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

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, 2982882 + ... + 2983097.

It is an arithmetic number, because the mean of its divisors is an integer number (69603100).

Almost surely, 2^644325732 is an apocalyptic number.

It is an amenable number.

644325732 is an abundant number, since it is smaller than the sum of its proper divisors (1026148668).

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

644325732 is a wasteful number, since it uses less digits than its factorization.

644325732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5965992 (or 5965984 counting only the distinct ones).

The product of its digits is 120960, while the sum is 36.

The square root of 644325732 is about 25383.5720890500. The cubic root of 644325732 is about 863.7110820244.

The spelling of 644325732 in words is "six hundred forty-four million, three hundred twenty-five thousand, seven hundred thirty-two".