644264438 has 8 divisors (see below), whose sum is σ = 986958432. Its totient is φ = 315278296.

The previous prime is 644264417. The next prime is 644264443. The reversal of 644264438 is 834462446.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644264395 and 644264404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3426845 + ... + 3427032.

It is an arithmetic number, because the mean of its divisors is an integer number (123369804).

Almost surely, 2^644264438 is an apocalyptic number.

644264438 is a deficient number, since it is larger than the sum of its proper divisors (342693994).

644264438 is a wasteful number, since it uses less digits than its factorization.

644264438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6853926.

The product of its digits is 442368, while the sum is 41.

The square root of 644264438 is about 25382.3647046527. The cubic root of 644264438 is about 863.6836931933.

The spelling of 644264438 in words is "six hundred forty-four million, two hundred sixty-four thousand, four hundred thirty-eight".