664564 has 24 divisors (see below), whose sum is σ = 1277640. Its totient is φ = 301056.

The previous prime is 664561. The next prime is 664571. The reversal of 664564 is 465466.

664564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 116964 + 547600 = 342^2 + 740^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1804 + ... + 2140.

It is an arithmetic number, because the mean of its divisors is an integer number (53235).

2⁶⁶⁴⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

664564 is a deficient number, since it is larger than the sum of its proper divisors (613076).

664564 is a wasteful number, since it uses less digits than its factorization.

664564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387 (or 385 counting only the distinct ones).

The product of its digits is 17280, while the sum is 31.

The square root of 664564 is about 815.2079489308. The cubic root of 664564 is about 87.2661073209.

The spelling of 664564 in words is "six hundred sixty-four thousand, five hundred sixty-four".