644874 has 16 divisors (see below), whose sum is σ = 1346112. Its totient is φ = 205568.

The previous prime is 644869. The next prime is 644881. The reversal of 644874 is 478446.

644874 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644874.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2199 + ... + 2474.

It is an arithmetic number, because the mean of its divisors is an integer number (84132).

2⁶⁴⁴⁸⁷⁴ is an apocalyptic number.

644874 is an abundant number, since it is smaller than the sum of its proper divisors (701238).

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

644874 is a wasteful number, since it uses less digits than its factorization.

644874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4701.

The product of its digits is 21504, while the sum is 33.

The square root of 644874 is about 803.0404722055. The cubic root of 644874 is about 86.3955994844.

The spelling of 644874 in words is "six hundred forty-four thousand, eight hundred seventy-four".