644947360 has 96 divisors (see below), whose sum is σ = 1637858880. Its totient is φ = 239112192.

The previous prime is 644947357. The next prime is 644947397. The reversal of 644947360 is 63749446.

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 15 ways as a sum of consecutive naturals, for example, 180471 + ... + 184009.

It is an arithmetic number, because the mean of its divisors is an integer number (17061030).

Almost surely, 2^644947360 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644947360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818929440).

644947360 is an abundant number, since it is smaller than the sum of its proper divisors (992911520).

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

644947360 is a wasteful number, since it uses less digits than its factorization.

644947360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3638 (or 3630 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 43.

The square root of 644947360 is about 25395.8138282671. The cubic root of 644947360 is about 863.9887544261.

The spelling of 644947360 in words is "six hundred forty-four million, nine hundred forty-seven thousand, three hundred sixty".