666009 has 16 divisors (see below), whose sum is σ = 1045440. Its totient is φ = 417600.

The previous prime is 665993. The next prime is 666013. The reversal of 666009 is 900666.

It is not a de Polignac number, because 666009 - 2⁴ = 665993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (666019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 267 + ... + 1184.

It is an arithmetic number, because the mean of its divisors is an integer number (65340).

2⁶⁶⁶⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

666009 is a deficient number, since it is larger than the sum of its proper divisors (379431).

666009 is a wasteful number, since it uses less digits than its factorization.

666009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1477 (or 1471 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 666009 is about 816.0937446152. The cubic root of 666009 is about 87.3293107847.

The spelling of 666009 in words is "six hundred sixty-six thousand, nine".