13809209 has 2 divisors, whose sum is σ = 13809210. Its totient is φ = 13809208.

The previous prime is 13809179. The next prime is 13809227. The reversal of 13809209 is 90290831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13213225 + 595984 = 3635^2 + 772^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13809209 is a prime.

It is not a weakly prime, because it can be changed into another prime (13809709) 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 as a sum of consecutive naturals, namely, 6904604 + 6904605.

It is an arithmetic number, because the mean of its divisors is an integer number (6904605).

Almost surely, 2^13809209 is an apocalyptic number.

It is an amenable number.

13809209 is a deficient number, since it is larger than the sum of its proper divisors (1).

13809209 is an equidigital number, since it uses as much as digits as its factorization.

13809209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 13809209 is about 3716.0744072206. The cubic root of 13809209 is about 239.9143733892.

The spelling of 13809209 in words is "thirteen million, eight hundred nine thousand, two hundred nine".