11909509 has 2 divisors, whose sum is σ = 11909510. Its totient is φ = 11909508.

The previous prime is 11909507. The next prime is 11909519. The reversal of 11909509 is 90590911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10692900 + 1216609 = 3270^2 + 1103^2 .

It is a cyclic number.

It is not a de Polignac number, because 11909509 - 2¹ = 11909507 is a prime.

Together with 11909507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11909507) 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, 5954754 + 5954755.

It is an arithmetic number, because the mean of its divisors is an integer number (5954755).

Almost surely, 2^11909509 is an apocalyptic number.

It is an amenable number.

11909509 is a deficient number, since it is larger than the sum of its proper divisors (1).

11909509 is an equidigital number, since it uses as much as digits as its factorization.

11909509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3645, while the sum is 34.

The square root of 11909509 is about 3451.0156476029. The cubic root of 11909509 is about 228.3659162245.

The spelling of 11909509 in words is "eleven million, nine hundred nine thousand, five hundred nine".