644570764 has 6 divisors (see below), whose sum is σ = 1127998844. Its totient is φ = 322285380.

The previous prime is 644570749. The next prime is 644570777. The reversal of 644570764 is 467075446.

It is a self number, because there is not a number n which added to its sum of digits gives 644570764.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80571342 + ... + 80571349.

Almost surely, 2^644570764 is an apocalyptic number.

It is an amenable number.

644570764 is a deficient number, since it is larger than the sum of its proper divisors (483428080).

644570764 is a wasteful number, since it uses less digits than its factorization.

644570764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161142695 (or 161142693 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 43.

The square root of 644570764 is about 25388.3982165083. The cubic root of 644570764 is about 863.8205556550.

The spelling of 644570764 in words is "six hundred forty-four million, five hundred seventy thousand, seven hundred sixty-four".