666715666 has 8 divisors (see below), whose sum is σ = 1003269564. Its totient is φ = 332292480.

The previous prime is 666715657. The next prime is 666715703. The reversal of 666715666 is 666517666.

It is a happy number.

666715666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 534580641 + 132135025 = 23121^2 + 11495^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531895 + ... + 533146.

Almost surely, 2^666715666 is an apocalyptic number.

666715666 is a deficient number, since it is larger than the sum of its proper divisors (336553898).

666715666 is a wasteful number, since it uses less digits than its factorization.

666715666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1065356.

The product of its digits is 1632960, while the sum is 49.

The square root of 666715666 is about 25820.8378252914. The cubic root of 666715666 is about 873.6018666422.

The spelling of 666715666 in words is "six hundred sixty-six million, seven hundred fifteen thousand, six hundred sixty-six".