644877 has 12 divisors (see below), whose sum is σ = 944320. Its totient is φ = 424008.

The previous prime is 644869. The next prime is 644881. The reversal of 644877 is 778446.

It is a happy number.

644877 is a `hidden beast` number, since 644 + 8 + 7 + 7 = 666.

It is not a de Polignac number, because 644877 - 2³ = 644869 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644877.

It is not an unprimeable number, because it can be changed into a prime (644837) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 258 + ... + 1164.

2⁶⁴⁴⁸⁷⁷ is an apocalyptic number.

It is an amenable number.

644877 is a deficient number, since it is larger than the sum of its proper divisors (299443).

644877 is a wasteful number, since it uses less digits than its factorization.

644877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 992 (or 989 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 644877 is about 803.0423401042. The cubic root of 644877 is about 86.3957334570.

It can be divided in two parts, 644 and 877, that added together give a square (1521 = 39²).

The spelling of 644877 in words is "six hundred forty-four thousand, eight hundred seventy-seven".