644443844 has 24 divisors (see below), whose sum is σ = 1231070400. Its totient is φ = 292746080.

The previous prime is 644443823. The next prime is 644443867. The reversal of 644443844 is 448344446.

644443844 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 87497 + ... + 94575.

It is an arithmetic number, because the mean of its divisors is an integer number (51294600).

Almost surely, 2^644443844 is an apocalyptic number.

It is an amenable number.

644443844 is a deficient number, since it is larger than the sum of its proper divisors (586626556).

644443844 is a wasteful number, since it uses less digits than its factorization.

644443844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9163 (or 9161 counting only the distinct ones).

The product of its digits is 589824, while the sum is 41.

The square root of 644443844 is about 25385.8985265442. The cubic root of 644443844 is about 863.7638547165.

The spelling of 644443844 in words is "six hundred forty-four million, four hundred forty-three thousand, eight hundred forty-four".