644772 has 12 divisors (see below), whose sum is σ = 1504496. Its totient is φ = 214920.

The previous prime is 644767. The next prime is 644783. The reversal of 644772 is 277446.

644772 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644772.

It is an unprimeable number.

644772 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26854 + ... + 26877.

2⁶⁴⁴⁷⁷² is an apocalyptic number.

It is an amenable number.

644772 is an abundant number, since it is smaller than the sum of its proper divisors (859724).

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

644772 is a wasteful number, since it uses less digits than its factorization.

644772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53738 (or 53736 counting only the distinct ones).

The product of its digits is 9408, while the sum is 30.

The square root of 644772 is about 802.9769610643. The cubic root of 644772 is about 86.3910441677.

The spelling of 644772 in words is "six hundred forty-four thousand, seven hundred seventy-two".