665789987566 has 8 divisors (see below), whose sum is σ = 1089474525144. Its totient is φ = 302631812520.

The previous prime is 665789987543. The next prime is 665789987591.

665789987566 is nontrivially palindromic in base 10.

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

It is a self number, because there is not a number n which added to its sum of digits gives 665789987566.

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, 15131590605 + ... + 15131590648.

It is an arithmetic number, because the mean of its divisors is an integer number (136184315643).

Almost surely, 2^665789987566 is an apocalyptic number.

665789987566 is a deficient number, since it is larger than the sum of its proper divisors (423684537578).

665789987566 is a wasteful number, since it uses less digits than its factorization.

665789987566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30263181266.

The product of its digits is 8230118400, while the sum is 82.

The spelling of 665789987566 in words is "six hundred sixty-five billion, seven hundred eighty-nine million, nine hundred eighty-seven thousand, five hundred sixty-six".