664566 has 16 divisors (see below), whose sum is σ = 1519104. Its totient is φ = 189864.

The previous prime is 664561. The next prime is 664571. The reversal of 664566 is 665466.

It is an interprime number because it is at equal distance from previous prime (664561) and next prime (664571).

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7870 + ... + 7953.

It is an arithmetic number, because the mean of its divisors is an integer number (94944).

2⁶⁶⁴⁵⁶⁶ is an apocalyptic number.

664566 is an abundant number, since it is smaller than the sum of its proper divisors (854538).

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

664566 is a wasteful number, since it uses less digits than its factorization.

664566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15835.

The product of its digits is 25920, while the sum is 33.

The square root of 664566 is about 815.2091756108. The cubic root of 664566 is about 87.2661948630.

Subtracting 664566 from its reverse (665466), we obtain a square (900 = 30²).

The spelling of 664566 in words is "six hundred sixty-four thousand, five hundred sixty-six".