12991969191 has 4 divisors (see below), whose sum is σ = 17322625592. Its totient is φ = 8661312792.

The previous prime is 12991969189. The next prime is 12991969307. The reversal of 12991969191 is 19196919921.

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

It is not a de Polignac number, because 12991969191 - 2¹ = 12991969189 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 (12991969141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2165328196 + ... + 2165328201.

It is an arithmetic number, because the mean of its divisors is an integer number (4330656398).

Almost surely, 2^12991969191 is an apocalyptic number.

12991969191 is a deficient number, since it is larger than the sum of its proper divisors (4330656401).

12991969191 is an equidigital number, since it uses as much as digits as its factorization.

12991969191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4330656400.

The product of its digits is 708588, while the sum is 57.

The spelling of 12991969191 in words is "twelve billion, nine hundred ninety-one million, nine hundred sixty-nine thousand, one hundred ninety-one".