644605345 has 16 divisors (see below), whose sum is σ = 789797952. Its totient is φ = 504878400.

The previous prime is 644605279. The next prime is 644605393. The reversal of 644605345 is 543506446.

It is a de Polignac number, because none of the positive numbers 2^k-644605345 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136270 + ... + 140920.

It is an arithmetic number, because the mean of its divisors is an integer number (49362372).

Almost surely, 2^644605345 is an apocalyptic number.

It is an amenable number.

644605345 is a deficient number, since it is larger than the sum of its proper divisors (145192607).

644605345 is a wasteful number, since it uses less digits than its factorization.

644605345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5232.

The product of its (nonzero) digits is 172800, while the sum is 37.

The square root of 644605345 is about 25389.0792467943. The cubic root of 644605345 is about 863.8360032707.

The spelling of 644605345 in words is "six hundred forty-four million, six hundred five thousand, three hundred forty-five".