13215691 has 2 divisors, whose sum is σ = 13215692. Its totient is φ = 13215690.

The previous prime is 13215661. The next prime is 13215707. The reversal of 13215691 is 19651231.

It is a strong prime.

It is an emirp because it is prime and its reverse (19651231) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13215691 - 2¹⁷ = 13084619 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (13215661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6607845 + 6607846.

It is an arithmetic number, because the mean of its divisors is an integer number (6607846).

Almost surely, 2^13215691 is an apocalyptic number.

13215691 is a deficient number, since it is larger than the sum of its proper divisors (1).

13215691 is an equidigital number, since it uses as much as digits as its factorization.

13215691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620, while the sum is 28.

The square root of 13215691 is about 3635.3391863759. The cubic root of 13215691 is about 236.4267570394.

The spelling of 13215691 in words is "thirteen million, two hundred fifteen thousand, six hundred ninety-one".