644248924 has 24 divisors (see below), whose sum is σ = 1236816000. Its totient is φ = 291200880.

The previous prime is 644248889. The next prime is 644248937. The reversal of 644248924 is 429842446.

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, 33024 + ... + 48775.

It is an arithmetic number, because the mean of its divisors is an integer number (51534000).

Almost surely, 2^644248924 is an apocalyptic number.

It is an amenable number.

644248924 is a deficient number, since it is larger than the sum of its proper divisors (592567076).

644248924 is a wasteful number, since it uses less digits than its factorization.

644248924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81993 (or 81991 counting only the distinct ones).

The product of its digits is 442368, while the sum is 43.

The square root of 644248924 is about 25382.0590969291. The cubic root of 644248924 is about 863.6767605863.

The spelling of 644248924 in words is "six hundred forty-four million, two hundred forty-eight thousand, nine hundred twenty-four".