12913831921 has 4 divisors (see below), whose sum is σ = 13359136500. Its totient is φ = 12468527344.

The previous prime is 12913831883. The next prime is 12913831961.

12913831921 is nontrivially palindromic in base 10.

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 7767778225 + 5146053696 = 88135^2 + 71736^2 .

It is a cyclic number.

It is not a de Polignac number, because 12913831921 - 2¹⁵ = 12913799153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12913831961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222652246 + ... + 222652303.

It is an arithmetic number, because the mean of its divisors is an integer number (3339784125).

Almost surely, 2^12913831921 is an apocalyptic number.

It is an amenable number.

12913831921 is a deficient number, since it is larger than the sum of its proper divisors (445304579).

12913831921 is an equidigital number, since it uses as much as digits as its factorization.

12913831921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445304578.

The product of its digits is 23328, while the sum is 40.

The spelling of 12913831921 in words is "twelve billion, nine hundred thirteen million, eight hundred thirty-one thousand, nine hundred twenty-one".