644376744 has 96 divisors (see below), whose sum is σ = 1909252800. Its totient is φ = 194711040.

The previous prime is 644376739. The next prime is 644376751. The reversal of 644376744 is 447673446.

It is a self number, because there is not a number n which added to its sum of digits gives 644376744.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 341997 + ... + 343875.

It is an arithmetic number, because the mean of its divisors is an integer number (19888050).

Almost surely, 2^644376744 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644376744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (954626400).

644376744 is an abundant number, since it is smaller than the sum of its proper divisors (1264876056).

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

644376744 is a wasteful number, since it uses less digits than its factorization.

644376744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2335 (or 2328 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 45.

The square root of 644376744 is about 25384.5768922785. The cubic root of 644376744 is about 863.7338750853.

The spelling of 644376744 in words is "six hundred forty-four million, three hundred seventy-six thousand, seven hundred forty-four".