666808666 has 16 divisors (see below), whose sum is σ = 1034765928. Its totient is φ = 322048000.

The previous prime is 666808657. The next prime is 666808669.

666808666 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 4 ways, for example, as 365612641 + 301196025 = 19121^2 + 17355^2 .

It is not an unprimeable number, because it can be changed into a prime (666808669) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31975 + ... + 48538.

Almost surely, 2^666808666 is an apocalyptic number.

666808666 is a deficient number, since it is larger than the sum of its proper divisors (367957262).

666808666 is a wasteful number, since it uses less digits than its factorization.

666808666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80657.

The product of its (nonzero) digits is 2985984, while the sum is 52.

The square root of 666808666 is about 25822.6386335711. The cubic root of 666808666 is about 873.6424842549.

The spelling of 666808666 in words is "six hundred sixty-six million, eight hundred eight thousand, six hundred sixty-six".