644725941 has 16 divisors (see below), whose sum is σ = 917967360. Its totient is φ = 401607360.

The previous prime is 644725927. The next prime is 644725951. The reversal of 644725941 is 149527446.

It is not a de Polignac number, because 644725941 - 2⁵ = 644725909 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644725893 and 644725902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644725951) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 116830 + ... + 122223.

It is an arithmetic number, because the mean of its divisors is an integer number (57372960).

Almost surely, 2^644725941 is an apocalyptic number.

It is an amenable number.

644725941 is a deficient number, since it is larger than the sum of its proper divisors (273241419).

644725941 is a wasteful number, since it uses less digits than its factorization.

644725941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239116.

The product of its digits is 241920, while the sum is 42.

The square root of 644725941 is about 25391.4540938482. The cubic root of 644725941 is about 863.8898701686.

The spelling of 644725941 in words is "six hundred forty-four million, seven hundred twenty-five thousand, nine hundred forty-one".