644895118 has 16 divisors (see below), whose sum is σ = 1105948800. Its totient is φ = 276280056.

The previous prime is 644895107. The next prime is 644895151. The reversal of 644895118 is 811598446.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39205 + ... + 53167.

It is an arithmetic number, because the mean of its divisors is an integer number (69121800).

Almost surely, 2^644895118 is an apocalyptic number.

644895118 is a deficient number, since it is larger than the sum of its proper divisors (461053682).

644895118 is a wasteful number, since it uses less digits than its factorization.

644895118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17271.

The product of its digits is 276480, while the sum is 46.

The square root of 644895118 is about 25394.7852520946. The cubic root of 644895118 is about 863.9654255355.

The spelling of 644895118 in words is "six hundred forty-four million, eight hundred ninety-five thousand, one hundred eighteen".