644025 has 24 divisors (see below), whose sum is σ = 1103104. Its totient is φ = 331200.

The previous prime is 644009. The next prime is 644029. The reversal of 644025 is 520446.

It is a happy number.

It is not a de Polignac number, because 644025 - 2⁴ = 644009 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 643992 and 644010.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644025.

It is not an unprimeable number, because it can be changed into a prime (644029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2187 + ... + 2463.

2⁶⁴⁴⁰²⁵ is an apocalyptic number.

It is an amenable number.

644025 is a deficient number, since it is larger than the sum of its proper divisors (459079).

644025 is a wasteful number, since it uses less digits than its factorization.

644025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 316 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 644025 is about 802.5116821580. The cubic root of 644025 is about 86.3576685207.

The spelling of 644025 in words is "six hundred forty-four thousand, twenty-five".