12656661005 has 4 divisors (see below), whose sum is σ = 15187993212. Its totient is φ = 10125328800.

The previous prime is 12656660971. The next prime is 12656661013. The reversal of 12656661005 is 50016665621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2616220201 + 10040440804 = 51149^2 + 100202^2 .

It is a de Polignac number, because none of the positive numbers 2^k-12656661005 is a prime.

It is a super-2 number, since 2×12656661005² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12656661005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1265666096 + ... + 1265666105.

It is an arithmetic number, because the mean of its divisors is an integer number (3796998303).

Almost surely, 2^12656661005 is an apocalyptic number.

It is an amenable number.

12656661005 is a deficient number, since it is larger than the sum of its proper divisors (2531332207).

12656661005 is an equidigital number, since it uses as much as digits as its factorization.

12656661005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2531332206.

The product of its (nonzero) digits is 64800, while the sum is 38.

The spelling of 12656661005 in words is "twelve billion, six hundred fifty-six million, six hundred sixty-one thousand, five".