644525 has 24 divisors (see below), whose sum is σ = 952320. Its totient is φ = 423360.

The previous prime is 644519. The next prime is 644531. The reversal of 644525 is 525446.

It is an interprime number because it is at equal distance from previous prime (644519) and next prime (644531).

It is a de Polignac number, because none of the positive numbers 2^k-644525 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 644494 and 644503.

It is a congruent 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, 5012 + ... + 5138.

It is an arithmetic number, because the mean of its divisors is an integer number (39680).

2⁶⁴⁴⁵²⁵ is an apocalyptic number.

It is an amenable number.

644525 is a deficient number, since it is larger than the sum of its proper divisors (307795).

644525 is a wasteful number, since it uses less digits than its factorization.

644525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 168 counting only the distinct ones).

The product of its digits is 4800, while the sum is 26.

The square root of 644525 is about 802.8231436624. The cubic root of 644525 is about 86.3800111652.

The spelling of 644525 in words is "six hundred forty-four thousand, five hundred twenty-five".