644633165 has 8 divisors (see below), whose sum is σ = 843883488. Its totient is φ = 468824080.

The previous prime is 644633161. The next prime is 644633173. The reversal of 644633165 is 561336446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644633165 - 2² = 644633161 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644633161) 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, 5860247 + ... + 5860356.

It is an arithmetic number, because the mean of its divisors is an integer number (105485436).

Almost surely, 2^644633165 is an apocalyptic number.

It is an amenable number.

644633165 is a deficient number, since it is larger than the sum of its proper divisors (199250323).

644633165 is a wasteful number, since it uses less digits than its factorization.

644633165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11720619.

The product of its digits is 155520, while the sum is 38.

The square root of 644633165 is about 25389.6271142370. The cubic root of 644633165 is about 863.8484302914.

The spelling of 644633165 in words is "six hundred forty-four million, six hundred thirty-three thousand, one hundred sixty-five".