12919891 has 2 divisors, whose sum is σ = 12919892. Its totient is φ = 12919890.

The previous prime is 12919889. The next prime is 12919903. The reversal of 12919891 is 19891921.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12919891 - 2¹ = 12919889 is a prime.

Together with 12919889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (12919871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6459945 + 6459946.

It is an arithmetic number, because the mean of its divisors is an integer number (6459946).

Almost surely, 2^12919891 is an apocalyptic number.

12919891 is a deficient number, since it is larger than the sum of its proper divisors (1).

12919891 is an equidigital number, since it uses as much as digits as its factorization.

12919891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 40.

The square root of 12919891 is about 3594.4249887847. The cubic root of 12919891 is about 234.6494910470.

The spelling of 12919891 in words is "twelve million, nine hundred nineteen thousand, eight hundred ninety-one".