11691209 has 2 divisors, whose sum is σ = 11691210. Its totient is φ = 11691208.

The previous prime is 11691179. The next prime is 11691259. The reversal of 11691209 is 90219611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6864400 + 4826809 = 2620^2 + 2197^2 .

It is an emirp because it is prime and its reverse (90219611) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11691209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (11691259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5845604 + 5845605.

It is an arithmetic number, because the mean of its divisors is an integer number (5845605).

Almost surely, 2^11691209 is an apocalyptic number.

It is an amenable number.

11691209 is a deficient number, since it is larger than the sum of its proper divisors (1).

11691209 is an equidigital number, since it uses as much as digits as its factorization.

11691209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 11691209 is about 3419.2409976485. The cubic root of 11691209 is about 226.9619956171.

The spelling of 11691209 in words is "eleven million, six hundred ninety-one thousand, two hundred nine".