668664 has 48 divisors (see below), whose sum is σ = 1867320. Its totient is φ = 216000.

The previous prime is 668623. The next prime is 668671. The reversal of 668664 is 466866.

It is a super-2 number, since 2×668664² = 894223089792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

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 668664.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 2539 + ... + 2789.

2⁶⁶⁸⁶⁶⁴ 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 668664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (933660).

668664 is an abundant number, since it is smaller than the sum of its proper divisors (1198656).

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

668664 is a wasteful number, since it uses less digits than its factorization.

668664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300 (or 293 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 668664 is about 817.7187780649. The cubic root of 668664 is about 87.4452010622.

The spelling of 668664 in words is "six hundred sixty-eight thousand, six hundred sixty-four".