644903152 has 20 divisors (see below), whose sum is σ = 1273077000. Its totient is φ = 316367168.

The previous prime is 644903123. The next prime is 644903179. The reversal of 644903152 is 251309446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 379402 + ... + 381097.

It is an arithmetic number, because the mean of its divisors is an integer number (63653850).

Almost surely, 2^644903152 is an apocalyptic number.

It is an amenable number.

644903152 is a deficient number, since it is larger than the sum of its proper divisors (628173848).

644903152 is a wasteful number, since it uses less digits than its factorization.

644903152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760560 (or 760554 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 644903152 is about 25394.9434336838. The cubic root of 644903152 is about 863.9690132348.

The spelling of 644903152 in words is "six hundred forty-four million, nine hundred three thousand, one hundred fifty-two".