11666509 has 16 divisors (see below), whose sum is σ = 12612096. Its totient is φ = 10771200.

The previous prime is 11666491. The next prime is 11666521. The reversal of 11666509 is 90566611.

It is a cyclic number.

It is not a de Polignac number, because 11666509 - 2⁵ = 11666477 is a prime.

It is a super-2 number, since 2×11666509² = 272214864494162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11666549) 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, 85089 + ... + 85225.

It is an arithmetic number, because the mean of its divisors is an integer number (788256).

Almost surely, 2^11666509 is an apocalyptic number.

It is an amenable number.

11666509 is a deficient number, since it is larger than the sum of its proper divisors (945587).

11666509 is a wasteful number, since it uses less digits than its factorization.

11666509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 11666509 is about 3415.6271752052. The cubic root of 11666509 is about 226.8020488333.

The spelling of 11666509 in words is "eleven million, six hundred sixty-six thousand, five hundred nine".