644904367 has 12 divisors (see below), whose sum is σ = 686329200. Its totient is φ = 605854976.

The previous prime is 644904329. The next prime is 644904373. The reversal of 644904367 is 763409446.

It is not a de Polignac number, because 644904367 - 2¹⁵ = 644871599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644904307) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 185259 + ... + 188707.

It is an arithmetic number, because the mean of its divisors is an integer number (57194100).

Almost surely, 2^644904367 is an apocalyptic number.

644904367 is a deficient number, since it is larger than the sum of its proper divisors (41424833).

644904367 is a wasteful number, since it uses less digits than its factorization.

644904367 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4130 (or 4113 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 43.

The square root of 644904367 is about 25394.9673557577. The cubic root of 644904367 is about 863.9695558081.

The spelling of 644904367 in words is "six hundred forty-four million, nine hundred four thousand, three hundred sixty-seven".