644903338 has 8 divisors (see below), whose sum is σ = 976396032. Its totient is φ = 319437996.

The previous prime is 644903299. The next prime is 644903351. The reversal of 644903338 is 833309446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 644903338.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1506570 + ... + 1506997.

It is an arithmetic number, because the mean of its divisors is an integer number (122049504).

Almost surely, 2^644903338 is an apocalyptic number.

644903338 is a deficient number, since it is larger than the sum of its proper divisors (331492694).

644903338 is a wasteful number, since it uses less digits than its factorization.

644903338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3013676.

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 644903338 is about 25394.9470958299. The cubic root of 644903338 is about 863.9690962955.

The spelling of 644903338 in words is "six hundred forty-four million, nine hundred three thousand, three hundred thirty-eight".