644675 has 12 divisors (see below), whose sum is σ = 810216. Its totient is φ = 508800.

The previous prime is 644671. The next prime is 644687. The reversal of 644675 is 576446.

644675 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644675 - 2² = 644671 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644671) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2555 + ... + 2795.

It is an arithmetic number, because the mean of its divisors is an integer number (67518).

2⁶⁴⁴⁶⁷⁵ is an apocalyptic number.

644675 is a deficient number, since it is larger than the sum of its proper divisors (165541).

644675 is a wasteful number, since it uses less digits than its factorization.

644675 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358 (or 353 counting only the distinct ones).

The product of its digits is 20160, while the sum is 32.

The square root of 644675 is about 802.9165585539. The cubic root of 644675 is about 86.3867117052.

The spelling of 644675 in words is "six hundred forty-four thousand, six hundred seventy-five".