666404 has 6 divisors (see below), whose sum is σ = 1166214. Its totient is φ = 333200.

The previous prime is 666403. The next prime is 666427. The reversal of 666404 is 404666.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 88804 = 760^2 + 298^2 .

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83297 + ... + 83304.

It is an arithmetic number, because the mean of its divisors is an integer number (194369).

2⁶⁶⁶⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

666404 is a deficient number, since it is larger than the sum of its proper divisors (499810).

666404 is a wasteful number, since it uses less digits than its factorization.

666404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166605 (or 166603 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 666404 is about 816.3357152545. The cubic root of 666404 is about 87.3465719431.

The spelling of 666404 in words is "six hundred sixty-six thousand, four hundred four".