644729172 has 24 divisors (see below), whose sum is σ = 1521273600. Its totient is φ = 212494656.

The previous prime is 644729149. The next prime is 644729201. The reversal of 644729172 is 271927446.

644729172 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 300772 + ... + 302907.

It is an arithmetic number, because the mean of its divisors is an integer number (63386400).

Almost surely, 2^644729172 is an apocalyptic number.

It is an amenable number.

644729172 is an abundant number, since it is smaller than the sum of its proper divisors (876544428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644729172 is a wasteful number, since it uses less digits than its factorization.

644729172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603775 (or 603773 counting only the distinct ones).

The product of its digits is 169344, while the sum is 42.

The square root of 644729172 is about 25391.5177175371. The cubic root of 644729172 is about 863.8913132745.

The spelling of 644729172 in words is "six hundred forty-four million, seven hundred twenty-nine thousand, one hundred seventy-two".