644876 has 12 divisors (see below), whose sum is σ = 1134672. Its totient is φ = 320688.

The previous prime is 644869. The next prime is 644881. The reversal of 644876 is 678446.

644876 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

644876 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, 746 + ... + 1358.

It is an arithmetic number, because the mean of its divisors is an integer number (94556).

2⁶⁴⁴⁸⁷⁶ is an apocalyptic number.

It is an amenable number.

644876 is a deficient number, since it is larger than the sum of its proper divisors (489796).

644876 is a wasteful number, since it uses less digits than its factorization.

644876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880 (or 878 counting only the distinct ones).

The product of its digits is 32256, while the sum is 35.

The square root of 644876 is about 803.0417174718. The cubic root of 644876 is about 86.3956887995.

The spelling of 644876 in words is "six hundred forty-four thousand, eight hundred seventy-six".