13991309 has 2 divisors, whose sum is σ = 13991310. Its totient is φ = 13991308.

The previous prime is 13991303. The next prime is 13991333. The reversal of 13991309 is 90319931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11202409 + 2788900 = 3347^2 + 1670^2 .

It is a cyclic number.

It is not a de Polignac number, because 13991309 - 2⁴ = 13991293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13991303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6995654 + 6995655.

It is an arithmetic number, because the mean of its divisors is an integer number (6995655).

Almost surely, 2^13991309 is an apocalyptic number.

It is an amenable number.

13991309 is a deficient number, since it is larger than the sum of its proper divisors (1).

13991309 is an equidigital number, since it uses as much as digits as its factorization.

13991309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6561, while the sum is 35.

The square root of 13991309 is about 3740.4958227486. The cubic root of 13991309 is about 240.9643433643.

The spelling of 13991309 in words is "thirteen million, nine hundred ninety-one thousand, three hundred nine".