665880406036738 has 16 divisors (see below), whose sum is σ = 1000618691841720. Its totient is φ = 332341237581696.

The previous prime is 665880406036697. The next prime is 665880406036787. The reversal of 665880406036738 is 837630604088566.

It can be written as a sum of positive squares in 4 ways, for example, as 643486566159369 + 22393839877369 = 25367037^2 + 4732213^2 .

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, 95504133 + ... + 102238936.

Almost surely, 2^{665880406036738} is an apocalyptic number.

665880406036738 is a deficient number, since it is larger than the sum of its proper divisors (334738285804982).

665880406036738 is a wasteful number, since it uses less digits than its factorization.

665880406036738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197746101.

The product of its (nonzero) digits is 836075520, while the sum is 70.

The spelling of 665880406036738 in words is "six hundred sixty-five trillion, eight hundred eighty billion, four hundred six million, thirty-six thousand, seven hundred thirty-eight".