666408 has 16 divisors (see below), whose sum is σ = 1666080. Its totient is φ = 222128.

The previous prime is 666403. The next prime is 666427. The reversal of 666408 is 804666.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (666403) by changing a digit.

666408 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, 13860 + ... + 13907.

It is an arithmetic number, because the mean of its divisors is an integer number (104130).

2⁶⁶⁶⁴⁰⁸ is an apocalyptic number.

It is an amenable number.

666408 is an abundant number, since it is smaller than the sum of its proper divisors (999672).

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

666408 is a wasteful number, since it uses less digits than its factorization.

666408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27776 (or 27772 counting only the distinct ones).

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

The square root of 666408 is about 816.3381652232. The cubic root of 666408 is about 87.3467467047.

The spelling of 666408 in words is "six hundred sixty-six thousand, four hundred eight".