12666575057561 has 4 divisors (see below), whose sum is σ = 12701857996800. Its totient is φ = 12631292118324.

The previous prime is 12666575057509. The next prime is 12666575057597. The reversal of 12666575057561 is 16575057566621.

12666575057561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12666575057561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12666575057494 and 12666575057503.

It is not an unprimeable number, because it can be changed into a prime (12666575057861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17641469081 + ... + 17641469798.

It is an arithmetic number, because the mean of its divisors is an integer number (3175464499200).

Almost surely, 2^{12666575057561} is an apocalyptic number.

It is an amenable number.

12666575057561 is a deficient number, since it is larger than the sum of its proper divisors (35282939239).

12666575057561 is an equidigital number, since it uses as much as digits as its factorization.

12666575057561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35282939238.

The product of its (nonzero) digits is 79380000, while the sum is 62.

The spelling of 12666575057561 in words is "twelve trillion, six hundred sixty-six billion, five hundred seventy-five million, fifty-seven thousand, five hundred sixty-one".