664565 has 16 divisors (see below), whose sum is σ = 893376. Its totient is φ = 470400.

The previous prime is 664561. The next prime is 664571. The reversal of 664565 is 565466.

It is not a de Polignac number, because 664565 - 2² = 664561 is a prime.

It is a Curzon number.

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 664565.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2225 + ... + 2505.

It is an arithmetic number, because the mean of its divisors is an integer number (55836).

2⁶⁶⁴⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

664565 is a deficient number, since it is larger than the sum of its proper divisors (228811).

664565 is a wasteful number, since it uses less digits than its factorization.

664565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340.

The product of its digits is 21600, while the sum is 32.

The square root of 664565 is about 815.2085622710. The cubic root of 664565 is about 87.2661510920.

Subtracting from 664565 its reverse (565466), we obtain a palindrome (99099).

The spelling of 664565 in words is "six hundred sixty-four thousand, five hundred sixty-five".