644472165 has 16 divisors (see below), whose sum is σ = 1031531328. Its totient is φ = 343593216.

The previous prime is 644472161. The next prime is 644472187. The reversal of 644472165 is 561274446.

It is not a de Polignac number, because 644472165 - 2² = 644472161 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644472161) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 47149 + ... + 59261.

It is an arithmetic number, because the mean of its divisors is an integer number (64470708).

Almost surely, 2^644472165 is an apocalyptic number.

It is an amenable number.

644472165 is a deficient number, since it is larger than the sum of its proper divisors (387059163).

644472165 is a wasteful number, since it uses less digits than its factorization.

644472165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15668.

The product of its digits is 161280, while the sum is 39.

The square root of 644472165 is about 25386.4563300985. The cubic root of 644472165 is about 863.7765076409.

The spelling of 644472165 in words is "six hundred forty-four million, four hundred seventy-two thousand, one hundred sixty-five".