644869320 has 64 divisors (see below), whose sum is σ = 1981808640. Its totient is φ = 167769600.

The previous prime is 644869261. The next prime is 644869333. The reversal of 644869320 is 23968446.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60616 + ... + 70455.

It is an arithmetic number, because the mean of its divisors is an integer number (30965760).

Almost surely, 2^644869320 is an apocalyptic number.

644869320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644869320 is an abundant number, since it is smaller than the sum of its proper divisors (1336939320).

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

644869320 is a wasteful number, since it uses less digits than its factorization.

644869320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131126 (or 131122 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 644869320 is about 25394.2773080866. The cubic root of 644869320 is about 863.9539048625.

The spelling of 644869320 in words is "six hundred forty-four million, eight hundred sixty-nine thousand, three hundred twenty".