66564 has 27 divisors (see below), whose sum is σ = 172263. Its totient is φ = 21672.

The previous prime is 66553. The next prime is 66569. The reversal of 66564 is 46566.

66564 = T₂₅₇ + T₂₅₈.

The square root of 66564 is 258.

It is a perfect power (a square), and thus also a powerful number.

66564 is a `hidden beast` number, since 6 + 656 + 4 = 666.

Its product of digits (4320) is a multiple of the sum of its prime divisors (48).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66564.

It is not an unprimeable number, because it can be changed into a prime (66569) by changing a digit.

66564 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1527 + ... + 1569.

2⁶⁶⁵⁶⁴ is an apocalyptic number.

66564 is the 258-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66564

66564 is an abundant number, since it is smaller than the sum of its proper divisors (105699).

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

66564 is a wasteful number, since it uses less digits than its factorization.

66564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 48 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The cubic root of 66564 is about 40.5271879630.

It can be divided in two parts, 665 and 64, that added together give a 6-th power (729 = 3⁶).

The spelling of 66564 in words is "sixty-six thousand, five hundred sixty-four".