666505 has 16 divisors (see below), whose sum is σ = 927360. Its totient is φ = 450432.

The previous prime is 666493. The next prime is 666511. The reversal of 666505 is 505666.

It is a cyclic number.

It is not a de Polignac number, because 666505 - 2⁹ = 665993 is a prime.

It is a nialpdrome in base 7.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4726 + ... + 4864.

It is an arithmetic number, because the mean of its divisors is an integer number (57960).

2⁶⁶⁶⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

666505 is a deficient number, since it is larger than the sum of its proper divisors (260855).

666505 is a wasteful number, since it uses less digits than its factorization.

666505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 666505 is about 816.3975747147. The cubic root of 666505 is about 87.3509844607.

The spelling of 666505 in words is "six hundred sixty-six thousand, five hundred five".