644471164 has 6 divisors (see below), whose sum is σ = 1127824544. Its totient is φ = 322235580.

The previous prime is 644471131. The next prime is 644471213. The reversal of 644471164 is 461174446.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80558892 + ... + 80558899.

Almost surely, 2^644471164 is an apocalyptic number.

It is an amenable number.

644471164 is a deficient number, since it is larger than the sum of its proper divisors (483353380).

644471164 is a wasteful number, since it uses less digits than its factorization.

644471164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161117795 (or 161117793 counting only the distinct ones).

The product of its digits is 64512, while the sum is 37.

The square root of 644471164 is about 25386.4366148540. The cubic root of 644471164 is about 863.7760604322.

The spelling of 644471164 in words is "six hundred forty-four million, four hundred seventy-one thousand, one hundred sixty-four".