644306625 has 96 divisors (see below), whose sum is σ = 1252817280. Its totient is φ = 317520000.

The previous prime is 644306617. The next prime is 644306629. The reversal of 644306625 is 526603446.

644306625 is a `hidden beast` number, since 644 + 3 + 0 + 6 + 6 + 2 + 5 = 666.

644306625 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644306625 - 2³ = 644306617 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644306625.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644306629) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 918775 + ... + 919475.

It is an arithmetic number, because the mean of its divisors is an integer number (13050180).

Almost surely, 2^644306625 is an apocalyptic number.

It is an amenable number.

644306625 is a deficient number, since it is larger than the sum of its proper divisors (608510655).

644306625 is a wasteful number, since it uses less digits than its factorization.

644306625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784 (or 771 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 644306625 is about 25383.1957207913. The cubic root of 644306625 is about 863.7025443702.

The spelling of 644306625 in words is "six hundred forty-four million, three hundred six thousand, six hundred twenty-five".