644361916 has 48 divisors (see below), whose sum is σ = 1280240640. Its totient is φ = 281203520.

The previous prime is 644361911. The next prime is 644361989. The reversal of 644361916 is 619163446.

644361916 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 not an unprimeable number, because it can be changed into a prime (644361911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106665 + ... + 112543.

It is an arithmetic number, because the mean of its divisors is an integer number (26671680).

Almost surely, 2^644361916 is an apocalyptic number.

It is an amenable number.

644361916 is a deficient number, since it is larger than the sum of its proper divisors (635878724).

644361916 is a wasteful number, since it uses less digits than its factorization.

644361916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5994 (or 5992 counting only the distinct ones).

The product of its digits is 93312, while the sum is 40.

The square root of 644361916 is about 25384.2848234887. The cubic root of 644361916 is about 863.7272497975.

The spelling of 644361916 in words is "six hundred forty-four million, three hundred sixty-one thousand, nine hundred sixteen".