644504425 has 24 divisors (see below), whose sum is σ = 865899936. Its totient is φ = 473975040.

The previous prime is 644504401. The next prime is 644504431. The reversal of 644504425 is 524405446.

It is not a de Polignac number, because 644504425 - 2¹¹ = 644502377 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 642 + ... + 35908.

It is an arithmetic number, because the mean of its divisors is an integer number (36079164).

Almost surely, 2^644504425 is an apocalyptic number.

It is an amenable number.

644504425 is a deficient number, since it is larger than the sum of its proper divisors (221395511).

644504425 is a wasteful number, since it uses less digits than its factorization.

644504425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35337 (or 35332 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 34.

The square root of 644504425 is about 25387.0917003110. The cubic root of 644504425 is about 863.7909199340.

The spelling of 644504425 in words is "six hundred forty-four million, five hundred four thousand, four hundred twenty-five".