666424 has 16 divisors (see below), whose sum is σ = 1363320. Its totient is φ = 302880.

The previous prime is 666403. The next prime is 666427. The reversal of 666424 is 424666.

It is a junction number, because it is equal to n+sod(n) for n = 666392 and 666401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666427) by changing a digit.

666424 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3699 + ... + 3874.

2⁶⁶⁶⁴²⁴ is an apocalyptic number.

It is an amenable number.

666424 is an abundant number, since it is smaller than the sum of its proper divisors (696896).

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

666424 is a wasteful number, since it uses less digits than its factorization.

666424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7590 (or 7586 counting only the distinct ones).

The product of its digits is 6912, while the sum is 28.

The square root of 666424 is about 816.3479650247. The cubic root of 666424 is about 87.3474457443.

It can be divided in two parts, 6 and 66424, that added together give a triangular number (66430 = T₃₆₄).

The spelling of 666424 in words is "six hundred sixty-six thousand, four hundred twenty-four".