644629325 has 6 divisors (see below), whose sum is σ = 799340394. Its totient is φ = 515703440.

The previous prime is 644629291. The next prime is 644629331. The reversal of 644629325 is 523926446.

It can be written as a sum of positive squares in 3 ways, for example, as 109956196 + 534673129 = 10486^2 + 23123^2 .

It is not a de Polignac number, because 644629325 - 2¹⁰ = 644628301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12892562 + ... + 12892611.

It is an arithmetic number, because the mean of its divisors is an integer number (133223399).

Almost surely, 2^644629325 is an apocalyptic number.

It is an amenable number.

644629325 is a deficient number, since it is larger than the sum of its proper divisors (154711069).

644629325 is a wasteful number, since it uses less digits than its factorization.

644629325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25785183 (or 25785178 counting only the distinct ones).

The product of its digits is 311040, while the sum is 41.

The square root of 644629325 is about 25389.5514926908. The cubic root of 644629325 is about 863.8467150086.

The spelling of 644629325 in words is "six hundred forty-four million, six hundred twenty-nine thousand, three hundred twenty-five".