644706125 has 32 divisors (see below), whose sum is σ = 925067520. Its totient is φ = 439425600.

The previous prime is 644706061. The next prime is 644706187. The reversal of 644706125 is 521607446.

It is not a de Polignac number, because 644706125 - 2⁶ = 644706061 is a prime.

It is a super-2 number, since 2×644706125² = 831291975225031250, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

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, 149246 + ... + 153504.

It is an arithmetic number, because the mean of its divisors is an integer number (28908360).

Almost surely, 2^644706125 is an apocalyptic number.

It is an amenable number.

644706125 is a deficient number, since it is larger than the sum of its proper divisors (280361395).

644706125 is a wasteful number, since it uses less digits than its factorization.

644706125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4454 (or 4444 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 644706125 is about 25391.0638808223. The cubic root of 644706125 is about 863.8810193706.

The spelling of 644706125 in words is "six hundred forty-four million, seven hundred six thousand, one hundred twenty-five".