13731209 has 2 divisors, whose sum is σ = 13731210. Its totient is φ = 13731208.

The previous prime is 13731197. The next prime is 13731217. The reversal of 13731209 is 90213731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13690000 + 41209 = 3700^2 + 203^2 .

It is an emirp because it is prime and its reverse (90213731) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13731209 is a prime.

It is a super-2 number, since 2×13731209² = 377092201203362, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (13731259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6865604 + 6865605.

It is an arithmetic number, because the mean of its divisors is an integer number (6865605).

Almost surely, 2^13731209 is an apocalyptic number.

It is an amenable number.

13731209 is a deficient number, since it is larger than the sum of its proper divisors (1).

13731209 is an equidigital number, since it uses as much as digits as its factorization.

13731209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 13731209 is about 3705.5645993559. The cubic root of 13731209 is about 239.4618090756.

The spelling of 13731209 in words is "thirteen million, seven hundred thirty-one thousand, two hundred nine".