644154972 has 24 divisors (see below), whose sum is σ = 1517912592. Its totient is φ = 212592000.

The previous prime is 644154899. The next prime is 644154991. The reversal of 644154972 is 279451446.

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, 264529 + ... + 266952.

It is an arithmetic number, because the mean of its divisors is an integer number (63246358).

Almost surely, 2^644154972 is an apocalyptic number.

It is an amenable number.

644154972 is an abundant number, since it is smaller than the sum of its proper divisors (873757620).

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

644154972 is a wasteful number, since it uses less digits than its factorization.

644154972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531589 (or 531587 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 644154972 is about 25380.2082733771. The cubic root of 644154972 is about 863.6347746909.

The spelling of 644154972 in words is "six hundred forty-four million, one hundred fifty-four thousand, nine hundred seventy-two".