12991289 has 4 divisors (see below), whose sum is σ = 13293456. Its totient is φ = 12689124.

The previous prime is 12991267. The next prime is 12991291. The reversal of 12991289 is 98219921.

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: 98219921 = 2131 ⋅46091.

It is a cyclic number.

It is not a de Polignac number, because 12991289 - 2²⁰ = 11942713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12991229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151019 + ... + 151104.

It is an arithmetic number, because the mean of its divisors is an integer number (3323364).

Almost surely, 2^12991289 is an apocalyptic number.

It is an amenable number.

12991289 is a deficient number, since it is larger than the sum of its proper divisors (302167).

12991289 is an equidigital number, since it uses as much as digits as its factorization.

12991289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302166.

The product of its digits is 23328, while the sum is 41.

The square root of 12991289 is about 3604.3430746809. The cubic root of 12991289 is about 235.0809378667.

The spelling of 12991289 in words is "twelve million, nine hundred ninety-one thousand, two hundred eighty-nine".