644869325 has 6 divisors (see below), whose sum is σ = 799637994. Its totient is φ = 515895440.

The previous prime is 644869261. The next prime is 644869333. The reversal of 644869325 is 523968446.

It can be written as a sum of positive squares in 3 ways, for example, as 23164969 + 621704356 = 4813^2 + 24934^2 .

It is not a de Polignac number, because 644869325 - 2⁶ = 644869261 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644869325.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12897362 + ... + 12897411.

It is an arithmetic number, because the mean of its divisors is an integer number (133272999).

Almost surely, 2^644869325 is an apocalyptic number.

It is an amenable number.

644869325 is a deficient number, since it is larger than the sum of its proper divisors (154768669).

644869325 is a wasteful number, since it uses less digits than its factorization.

644869325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25794783 (or 25794778 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 47.

The square root of 644869325 is about 25394.2774065339. The cubic root of 644869325 is about 863.9539070954.

The spelling of 644869325 in words is "six hundred forty-four million, eight hundred sixty-nine thousand, three hundred twenty-five".