666624 has 88 divisors (see below), whose sum is σ = 2096128. Its totient is φ = 184320.

The previous prime is 666607. The next prime is 666637. The reversal of 666624 is 426666.

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

It is a junction number, because it is equal to n+sod(n) for n = 666591 and 666600.

It is a congruent number.

It is an unprimeable number.

666624 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 (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21489 + ... + 21519.

2⁶⁶⁶⁶²⁴ is an apocalyptic number.

666624 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1048064).

666624 is an abundant number, since it is smaller than the sum of its proper divisors (1429504).

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

666624 is a wasteful number, since it uses less digits than its factorization.

666624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61 (or 43 counting only the distinct ones).

The product of its digits is 10368, while the sum is 30.

The square root of 666624 is about 816.4704526191. The cubic root of 666624 is about 87.3561827955.

It can be divided in two parts, 66662 and 4, that added together give a palindrome (66666).

The spelling of 666624 in words is "six hundred sixty-six thousand, six hundred twenty-four".