644489373 has 32 divisors (see below), whose sum is σ = 963228672. Its totient is φ = 379913600.

The previous prime is 644489353. The next prime is 644489389. The reversal of 644489373 is 373984446.

It is not a de Polignac number, because 644489373 - 2⁶ = 644489309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644489303) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 680086 + ... + 681032.

It is an arithmetic number, because the mean of its divisors is an integer number (30100896).

Almost surely, 2^644489373 is an apocalyptic number.

It is an amenable number.

644489373 is a deficient number, since it is larger than the sum of its proper divisors (318739299).

644489373 is a wasteful number, since it uses less digits than its factorization.

644489373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1505.

The product of its digits is 1741824, while the sum is 48.

The square root of 644489373 is about 25386.7952487115. The cubic root of 644489373 is about 863.7841954484.

The spelling of 644489373 in words is "six hundred forty-four million, four hundred eighty-nine thousand, three hundred seventy-three".