645564 has 24 divisors (see below), whose sum is σ = 1572480. Its totient is φ = 205744.

The previous prime is 645529. The next prime is 645571. The reversal of 645564 is 465546.

It is a congruent number.

It is an unprimeable number.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 894 + ... + 1445.

It is an arithmetic number, because the mean of its divisors is an integer number (65520).

2⁶⁴⁵⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

645564 is an abundant number, since it is smaller than the sum of its proper divisors (926916).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645564 is a wasteful number, since it uses less digits than its factorization.

645564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369 (or 2367 counting only the distinct ones).

The product of its digits is 14400, while the sum is 30.

The square root of 645564 is about 803.4699745479. The cubic root of 645564 is about 86.4264022535.

The spelling of 645564 in words is "six hundred forty-five thousand, five hundred sixty-four".