644773036 has 24 divisors (see below), whose sum is σ = 1149120000. Its totient is φ = 316499664.

The previous prime is 644773033. The next prime is 644773039. The reversal of 644773036 is 630377446.

It is an interprime number because it is at equal distance from previous prime (644773033) and next prime (644773039).

It is a self number, because there is not a number n which added to its sum of digits gives 644773036.

It is not an unprimeable number, because it can be changed into a prime (644773033) 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, 50865 + ... + 62263.

It is an arithmetic number, because the mean of its divisors is an integer number (47880000).

Almost surely, 2^644773036 is an apocalyptic number.

It is an amenable number.

644773036 is a deficient number, since it is larger than the sum of its proper divisors (504346964).

644773036 is a wasteful number, since it uses less digits than its factorization.

644773036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11661 (or 11659 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 40.

The square root of 644773036 is about 25392.3814558619. The cubic root of 644773036 is about 863.9109043787.

The spelling of 644773036 in words is "six hundred forty-four million, seven hundred seventy-three thousand, thirty-six".