644595245 has 24 divisors (see below), whose sum is σ = 928839168. Its totient is φ = 427744800.

The previous prime is 644595233. The next prime is 644595251. The reversal of 644595245 is 542595446.

It is a de Polignac number, because none of the positive numbers 2^k-644595245 is a prime.

It is a super-2 number, since 2×644595245² = 831006059753220050, which contains 22 as substring.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644595196 and 644595205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34841 + ... + 50030.

It is an arithmetic number, because the mean of its divisors is an integer number (38701632).

Almost surely, 2^644595245 is an apocalyptic number.

It is an amenable number.

644595245 is a deficient number, since it is larger than the sum of its proper divisors (284243923).

644595245 is a wasteful number, since it uses less digits than its factorization.

644595245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84921 (or 84914 counting only the distinct ones).

The product of its digits is 864000, while the sum is 44.

The square root of 644595245 is about 25388.8803415984. The cubic root of 644595245 is about 863.8314915752.

The spelling of 644595245 in words is "six hundred forty-four million, five hundred ninety-five thousand, two hundred forty-five".