665696808696566 has 8 divisors (see below), whose sum is σ = 998628128070024. Its totient is φ = 332820766006560.

The previous prime is 665696808696551. The next prime is 665696808696697.

665696808696566 is nontrivially palindromic in base 10.

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

It is a super-2 number, since 2×665696808696566² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

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, 13819140755 + ... + 13819188926.

It is an arithmetic number, because the mean of its divisors is an integer number (124828516008753).

Almost surely, 2^{665696808696566} is an apocalyptic number.

665696808696566 is a deficient number, since it is larger than the sum of its proper divisors (332931319373458).

665696808696566 is a wasteful number, since it uses less digits than its factorization.

665696808696566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27638341726.

The product of its (nonzero) digits is 217678233600, while the sum is 92.

The spelling of 665696808696566 in words is "six hundred sixty-five trillion, six hundred ninety-six billion, eight hundred eight million, six hundred ninety-six thousand, five hundred sixty-six".