665168061668 has 18 divisors (see below), whose sum is σ = 1279486499718. Its totient is φ = 302349118720.

The previous prime is 665168061659. The next prime is 665168061683. The reversal of 665168061668 is 866160861566.

It can be written as a sum of positive squares in only one way, i.e., 335058060964 + 330110000704 = 578842^2 + 574552^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 687156605 + ... + 687157572.

Almost surely, 2^665168061668 is an apocalyptic number.

It is an amenable number.

665168061668 is a deficient number, since it is larger than the sum of its proper divisors (614318438050).

665168061668 is a wasteful number, since it uses less digits than its factorization.

665168061668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1374314203 (or 1374314190 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 59.

The spelling of 665168061668 in words is "six hundred sixty-five billion, one hundred sixty-eight million, sixty-one thousand, six hundred sixty-eight".