644925 has 12 divisors (see below), whose sum is σ = 1066400. Its totient is φ = 343920.

The previous prime is 644923. The next prime is 644933. The reversal of 644925 is 529446.

It is not a de Polignac number, because 644925 - 2¹ = 644923 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644892 and 644901.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644925.

It is not an unprimeable number, because it can be changed into a prime (644923) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 4225 + ... + 4374.

2⁶⁴⁴⁹²⁵ is an apocalyptic number.

It is an amenable number.

644925 is a deficient number, since it is larger than the sum of its proper divisors (421475).

644925 is a wasteful number, since it uses less digits than its factorization.

644925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8612 (or 8607 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 644925 is about 803.0722258925. The cubic root of 644925 is about 86.3978769626.

The spelling of 644925 in words is "six hundred forty-four thousand, nine hundred twenty-five".