11810991209 has 4 divisors (see below), whose sum is σ = 11811303504. Its totient is φ = 11810678916.

The previous prime is 11810991197. The next prime is 11810991229. The reversal of 11810991209 is 90219901811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11810991209 - 2⁸ = 11810990953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11810991229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90107 + ... + 178160.

It is an arithmetic number, because the mean of its divisors is an integer number (2952825876).

Almost surely, 2^11810991209 is an apocalyptic number.

It is an amenable number.

11810991209 is a deficient number, since it is larger than the sum of its proper divisors (312295).

11810991209 is an equidigital number, since it uses as much as digits as its factorization.

11810991209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312294.

The product of its (nonzero) digits is 11664, while the sum is 41.

The spelling of 11810991209 in words is "eleven billion, eight hundred ten million, nine hundred ninety-one thousand, two hundred nine".