666909666 has 32 divisors (see below), whose sum is σ = 1496707200. Its totient is φ = 220100400.

The previous prime is 666909641. The next prime is 666909673.

666909666 is nontrivially palindromic in base 10.

666909666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 55686 + ... + 66593.

It is an arithmetic number, because the mean of its divisors is an integer number (46772100).

Almost surely, 2^666909666 is an apocalyptic number.

666909666 is an abundant number, since it is smaller than the sum of its proper divisors (829797534).

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

666909666 is a wasteful number, since it uses less digits than its factorization.

666909666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122391 (or 122385 counting only the distinct ones).

The product of its (nonzero) digits is 3779136, while the sum is 54.

The square root of 666909666 is about 25824.5942078477. The cubic root of 666909666 is about 873.6865915782.

The spelling of 666909666 in words is "six hundred sixty-six million, nine hundred nine thousand, six hundred sixty-six".