644523525 has 36 divisors (see below), whose sum is σ = 1156543908. Its totient is φ = 343111680.

The previous prime is 644523479. The next prime is 644523547. The reversal of 644523525 is 525325446.

644523525 is a `hidden beast` number, since 644 + 5 + 2 + 3 + 5 + 2 + 5 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 29582721 + 614940804 = 5439^2 + 24798^2 .

It is not a de Polignac number, because 644523525 - 2¹⁴ = 644507141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644523525.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 135589 + ... + 140261.

Almost surely, 2^644523525 is an apocalyptic number.

It is an amenable number.

644523525 is a deficient number, since it is larger than the sum of its proper divisors (512020383).

644523525 is a wasteful number, since it uses less digits than its factorization.

644523525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5302 (or 5294 counting only the distinct ones).

The product of its digits is 144000, while the sum is 36.

The square root of 644523525 is about 25387.4678729487. The cubic root of 644523525 is about 863.7994527141.

The spelling of 644523525 in words is "six hundred forty-four million, five hundred twenty-three thousand, five hundred twenty-five".