11918509 has 2 divisors, whose sum is σ = 11918510. Its totient is φ = 11918508.

The previous prime is 11918503. The next prime is 11918519. The reversal of 11918509 is 90581911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11492100 + 426409 = 3390^2 + 653^2 .

It is a cyclic number.

It is not a de Polignac number, because 11918509 - 2⁷ = 11918381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11918503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5959254 + 5959255.

It is an arithmetic number, because the mean of its divisors is an integer number (5959255).

Almost surely, 2^11918509 is an apocalyptic number.

It is an amenable number.

11918509 is a deficient number, since it is larger than the sum of its proper divisors (1).

11918509 is an equidigital number, since it uses as much as digits as its factorization.

11918509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 34.

The square root of 11918509 is about 3452.3193652963. The cubic root of 11918509 is about 228.4234270123.

The spelling of 11918509 in words is "eleven million, nine hundred eighteen thousand, five hundred nine".