666997799666 has 16 divisors (see below), whose sum is σ = 1091697982848. Its totient is φ = 303112196400.

The previous prime is 666997799639. The next prime is 666997799681.

It is a happy number.

666997799666 is nontrivially palindromic in base 10.

It is a zygodrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3331610 + ... + 3526133.

It is an arithmetic number, because the mean of its divisors is an integer number (68231123928).

Almost surely, 2^666997799666 is an apocalyptic number.

666997799666 is a deficient number, since it is larger than the sum of its proper divisors (424700183182).

666997799666 is a wasteful number, since it uses less digits than its factorization.

666997799666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6862177.

The product of its digits is 14999390784, while the sum is 86.

The spelling of 666997799666 in words is "six hundred sixty-six billion, nine hundred ninety-seven million, seven hundred ninety-nine thousand, six hundred sixty-six".