644993832 has 64 divisors (see below), whose sum is σ = 1846627200. Its totient is φ = 183905280.

The previous prime is 644993819. The next prime is 644993861. The reversal of 644993832 is 238399446.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83844 + ... + 91212.

It is an arithmetic number, because the mean of its divisors is an integer number (28853550).

Almost surely, 2^644993832 is an apocalyptic number.

It is an amenable number.

644993832 is an abundant number, since it is smaller than the sum of its proper divisors (1201633368).

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

644993832 is a wasteful number, since it uses less digits than its factorization.

644993832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7906 (or 7902 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 48.

The square root of 644993832 is about 25396.7287657289. The cubic root of 644993832 is about 864.0095056396.

The spelling of 644993832 in words is "six hundred forty-four million, nine hundred ninety-three thousand, eight hundred thirty-two".