644523356 has 12 divisors (see below), whose sum is σ = 1164300480. Its totient is φ = 311866080.

The previous prime is 644523311. The next prime is 644523367. The reversal of 644523356 is 653325446.

It is a happy number.

644523356 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2598761 + ... + 2599008.

It is an arithmetic number, because the mean of its divisors is an integer number (97025040).

Almost surely, 2^644523356 is an apocalyptic number.

It is an amenable number.

644523356 is a deficient number, since it is larger than the sum of its proper divisors (519777124).

644523356 is a wasteful number, since it uses less digits than its factorization.

644523356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5197804 (or 5197802 counting only the distinct ones).

The product of its digits is 259200, while the sum is 38.

The square root of 644523356 is about 25387.4645445346. The cubic root of 644523356 is about 863.7993772154.

The spelling of 644523356 in words is "six hundred forty-four million, five hundred twenty-three thousand, three hundred fifty-six".