11909 has 2 divisors, whose sum is σ = 11910. Its totient is φ = 11908.

The previous prime is 11903. The next prime is 11923. The reversal of 11909 is 90911.

11909 = 62² + 63² + 64².

11909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9409 + 2500 = 97^2 + 50^2 .

It is an emirp because it is prime and its reverse (90911) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11909 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5954 + 5955.

It is an arithmetic number, because the mean of its divisors is an integer number (5955).

2¹¹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

11909 is a deficient number, since it is larger than the sum of its proper divisors (1).

11909 is an equidigital number, since it uses as much as digits as its factorization.

11909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81, while the sum is 20.

The square root of 11909 is about 109.1283647820. The cubic root of 11909 is about 22.8362662804.

It can be divided in two parts, 11 and 909, that multiplied together give a palindrome (9999).

The spelling of 11909 in words is "eleven thousand, nine hundred nine".