644674 has 16 divisors (see below), whose sum is σ = 1042848. Its totient is φ = 297792.

The previous prime is 644671. The next prime is 644687. The reversal of 644674 is 476446.

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 7 ways as a sum of consecutive naturals, for example, 2137 + ... + 2419.

It is an arithmetic number, because the mean of its divisors is an integer number (65178).

2⁶⁴⁴⁶⁷⁴ is an apocalyptic number.

644674 is a deficient number, since it is larger than the sum of its proper divisors (398174).

644674 is a wasteful number, since it uses less digits than its factorization.

644674 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369.

The product of its digits is 16128, while the sum is 31.

The square root of 644674 is about 802.9159358239. The cubic root of 644674 is about 86.3866670384.

The spelling of 644674 in words is "six hundred forty-four thousand, six hundred seventy-four".