644216936 has 32 divisors (see below), whose sum is σ = 1375012800. Its totient is φ = 280093440.

The previous prime is 644216893. The next prime is 644216939. The reversal of 644216936 is 639612446.

644216936 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 644216893 and 644216902.

It is not an unprimeable number, because it can be changed into a prime (644216939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157121 + ... + 161168.

It is an arithmetic number, because the mean of its divisors is an integer number (42969150).

Almost surely, 2^644216936 is an apocalyptic number.

It is an amenable number.

644216936 is an abundant number, since it is smaller than the sum of its proper divisors (730795864).

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

644216936 is a wasteful number, since it uses less digits than its factorization.

644216936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318329 (or 318325 counting only the distinct ones).

The product of its digits is 186624, while the sum is 41.

The square root of 644216936 is about 25381.4289589850. The cubic root of 644216936 is about 863.6624660342.

The spelling of 644216936 in words is "six hundred forty-four million, two hundred sixteen thousand, nine hundred thirty-six".