12642129681 has 4 divisors (see below), whose sum is σ = 16856172912. Its totient is φ = 8428086452.

The previous prime is 12642129677. The next prime is 12642129719. The reversal of 12642129681 is 18692124621.

12642129681 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, and also an emirpimes, since its reverse is a distinct semiprime: 18692124621 = 3 ⋅6230708207.

It is a cyclic number.

It is not a de Polignac number, because 12642129681 - 2² = 12642129677 is a prime.

It is a super-2 number, since 2×12642129681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12642129631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2107021611 + ... + 2107021616.

It is an arithmetic number, because the mean of its divisors is an integer number (4214043228).

Almost surely, 2^12642129681 is an apocalyptic number.

It is an amenable number.

12642129681 is a deficient number, since it is larger than the sum of its proper divisors (4214043231).

12642129681 is an equidigital number, since it uses as much as digits as its factorization.

12642129681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4214043230.

The product of its digits is 82944, while the sum is 42.

The spelling of 12642129681 in words is "twelve billion, six hundred forty-two million, one hundred twenty-nine thousand, six hundred eighty-one".