66664 has 16 divisors (see below), whose sum is σ = 134820. Its totient is φ = 30720.

The previous prime is 66653. The next prime is 66683. The reversal of 66664 is 46666.

It can be written as a sum of positive squares in 2 ways, for example, as 66564 + 100 = 258^2 + 10^2 .

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 217 + ... + 424.

2⁶⁶⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

66664 is an abundant number, since it is smaller than the sum of its proper divisors (68156).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67410).

66664 is a wasteful number, since it uses less digits than its factorization.

66664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660 (or 656 counting only the distinct ones).

The product of its digits is 5184, while the sum is 28.

The square root of 66664 is about 258.1937257177. The cubic root of 66664 is about 40.5474726564.

It can be divided in two parts, 6666 and 4, that added together give a triangular number (6670 = T₁₁₅).

The spelling of 66664 in words is "sixty-six thousand, six hundred sixty-four".