644484878 has 16 divisors (see below), whose sum is σ = 985370400. Its totient is φ = 316087296.

The previous prime is 644484877. The next prime is 644484881. The reversal of 644484878 is 878484446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644484871) 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, 7223 + ... + 36621.

It is an arithmetic number, because the mean of its divisors is an integer number (61585650).

Almost surely, 2^644484878 is an apocalyptic number.

644484878 is a deficient number, since it is larger than the sum of its proper divisors (340885522).

644484878 is a wasteful number, since it uses less digits than its factorization.

644484878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29611.

The product of its digits is 5505024, while the sum is 53.

The square root of 644484878 is about 25386.7067182807. The cubic root of 644484878 is about 863.7821872855.

The spelling of 644484878 in words is "six hundred forty-four million, four hundred eighty-four thousand, eight hundred seventy-eight".