12156805621 has 8 divisors (see below), whose sum is σ = 13004613720. Its totient is φ = 11323742208.

The previous prime is 12156805607. The next prime is 12156805649. The reversal of 12156805621 is 12650865121.

12156805621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 6195421521 + 5961384100 = 78711^2 + 77210^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12156805621 - 2²³ = 12148417013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12156805021) 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 7 ways as a sum of consecutive naturals, for example, 3684466 + ... + 3687763.

It is an arithmetic number, because the mean of its divisors is an integer number (1625576715).

Almost surely, 2^12156805621 is an apocalyptic number.

It is an amenable number.

12156805621 is a deficient number, since it is larger than the sum of its proper divisors (847808099).

12156805621 is an equidigital number, since it uses as much as digits as its factorization.

12156805621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7372343.

The product of its (nonzero) digits is 28800, while the sum is 37.

The spelling of 12156805621 in words is "twelve billion, one hundred fifty-six million, eight hundred five thousand, six hundred twenty-one".