644373345 has 32 divisors (see below), whose sum is σ = 1285401600. Its totient is φ = 267791040.

The previous prime is 644373307. The next prime is 644373377. The reversal of 644373345 is 543373446.

It is not a de Polignac number, because 644373345 - 2⁸ = 644373089 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 277795 + ... + 280104.

It is an arithmetic number, because the mean of its divisors is an integer number (40168800).

Almost surely, 2^644373345 is an apocalyptic number.

It is an amenable number.

644373345 is a deficient number, since it is larger than the sum of its proper divisors (641028255).

644373345 is a wasteful number, since it uses less digits than its factorization.

644373345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557925.

The product of its digits is 362880, while the sum is 39.

The square root of 644373345 is about 25384.5099420887. The cubic root of 644373345 is about 863.7323563896.

The spelling of 644373345 in words is "six hundred forty-four million, three hundred seventy-three thousand, three hundred forty-five".