66864 has 40 divisors (see below), whose sum is σ = 198400. Its totient is φ = 19008.

The previous prime is 66863. The next prime is 66877. The reversal of 66864 is 46866.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66863) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 237 + ... + 435.

It is an arithmetic number, because the mean of its divisors is an integer number (4960).

2⁶⁶⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99200).

66864 is an abundant number, since it is smaller than the sum of its proper divisors (131536).

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

66864 is a wasteful number, since it uses less digits than its factorization.

66864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217 (or 211 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

The square root of 66864 is about 258.5807417423. The cubic root of 66864 is about 40.5879812678.

The spelling of 66864 in words is "sixty-six thousand, eight hundred sixty-four".