13216991 has 2 divisors, whose sum is σ = 13216992. Its totient is φ = 13216990.

The previous prime is 13216969. The next prime is 13216993. The reversal of 13216991 is 19961231.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13216991 is a prime.

It is a Sophie Germain prime.

Together with 13216993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13216993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6608495 + 6608496.

It is an arithmetic number, because the mean of its divisors is an integer number (6608496).

Almost surely, 2^13216991 is an apocalyptic number.

13216991 is a deficient number, since it is larger than the sum of its proper divisors (1).

13216991 is an equidigital number, since it uses as much as digits as its factorization.

13216991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 32.

The square root of 13216991 is about 3635.5179823513. The cubic root of 13216991 is about 236.4345090545.

The spelling of 13216991 in words is "thirteen million, two hundred sixteen thousand, nine hundred ninety-one".