644774373 has 12 divisors (see below), whose sum is σ = 937056640. Its totient is φ = 427211496.

The previous prime is 644774353. The next prime is 644774381. The reversal of 644774373 is 373477446.

It is not a de Polignac number, because 644774373 - 2⁹ = 644773861 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 (644774303) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 218293 + ... + 221226.

Almost surely, 2^644774373 is an apocalyptic number.

It is an amenable number.

644774373 is a deficient number, since it is larger than the sum of its proper divisors (292282267).

644774373 is a wasteful number, since it uses less digits than its factorization.

644774373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439688 (or 439685 counting only the distinct ones).

The product of its digits is 1185408, while the sum is 45.

The square root of 644774373 is about 25392.4077826424. The cubic root of 644774373 is about 863.9115015129.

The spelling of 644774373 in words is "six hundred forty-four million, seven hundred seventy-four thousand, three hundred seventy-three".