644468 has 24 divisors (see below), whose sum is σ = 1251264. Its totient is φ = 288000.

The previous prime is 644447. The next prime is 644489. The reversal of 644468 is 864446.

It is an interprime number because it is at equal distance from previous prime (644447) and next prime (644489).

It is a congruent number.

It is an unprimeable number.

644468 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4193 + ... + 4343.

It is an arithmetic number, because the mean of its divisors is an integer number (52136).

2⁶⁴⁴⁴⁶⁸ is an apocalyptic number.

It is an amenable number.

644468 is a deficient number, since it is larger than the sum of its proper divisors (606796).

644468 is a wasteful number, since it uses less digits than its factorization.

644468 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263 (or 261 counting only the distinct ones).

The product of its digits is 18432, while the sum is 32.

The square root of 644468 is about 802.7876431535. The cubic root of 644468 is about 86.3774646874.

The spelling of 644468 in words is "six hundred forty-four thousand, four hundred sixty-eight".