766638836666 has 16 divisors (see below), whose sum is σ = 1190580049800. Its totient is φ = 369800332608.

The previous prime is 766638836549. The next prime is 766638836773. The reversal of 766638836666 is 666638836667.

It can be written as a sum of positive squares in 4 ways, for example, as 762976045225 + 3662791441 = 873485^2 + 60521^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 766638836666.

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, 5306225 + ... + 5448788.

Almost surely, 2^766638836666 is an apocalyptic number.

766638836666 is a deficient number, since it is larger than the sum of its proper divisors (423941213134).

766638836666 is a wasteful number, since it uses less digits than its factorization.

766638836666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10756273.

The product of its digits is 1128701952, while the sum is 71.

Subtracting from 766638836666 its reverse (666638836667), we obtain a palindrome (99999999999).

The spelling of 766638836666 in words is "seven hundred sixty-six billion, six hundred thirty-eight million, eight hundred thirty-six thousand, six hundred sixty-six".