12961660665666 has 64 divisors (see below), whose sum is σ = 27432832204800. Its totient is φ = 4071390710400.

The previous prime is 12961660665643. The next prime is 12961660665683. The reversal of 12961660665666 is 66656606616921.

It is a super-3 number, since 3×12961660665666³ (a number of 40 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 12961660665597 and 12961660665606.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 484915390 + ... + 484942118.

It is an arithmetic number, because the mean of its divisors is an integer number (428638003200).

Almost surely, 2^{12961660665666} is an apocalyptic number.

12961660665666 is an abundant number, since it is smaller than the sum of its proper divisors (14471171539134).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12961660665666 is a wasteful number, since it uses less digits than its factorization.

12961660665666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49215.

The product of its (nonzero) digits is 151165440, while the sum is 66.

The spelling of 12961660665666 in words is "twelve trillion, nine hundred sixty-one billion, six hundred sixty million, six hundred sixty-five thousand, six hundred sixty-six".