12656798721 has 16 divisors (see below), whose sum is σ = 21429500800. Its totient is φ = 7232456304.

The previous prime is 12656798711. The next prime is 12656798729. The reversal of 12656798721 is 12789765621.

12656798721 is a `hidden beast` number, since 1 + 2 + 6 + 567 + 9 + 8 + 72 + 1 = 666.

It is not a de Polignac number, because 12656798721 - 2¹⁰ = 12656797697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12656798729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33483406 + ... + 33483783.

It is an arithmetic number, because the mean of its divisors is an integer number (1339343800).

Almost surely, 2^12656798721 is an apocalyptic number.

It is an amenable number.

12656798721 is a deficient number, since it is larger than the sum of its proper divisors (8772702079).

12656798721 is an equidigital number, since it uses as much as digits as its factorization.

12656798721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66967205 (or 66967199 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 54.

The spelling of 12656798721 in words is "twelve billion, six hundred fifty-six million, seven hundred ninety-eight thousand, seven hundred twenty-one".