11891612009 has 2 divisors, whose sum is σ = 11891612010. Its totient is φ = 11891612008.

The previous prime is 11891611969. The next prime is 11891612011. The reversal of 11891612009 is 90021619811.

11891612009 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11670048784 + 221563225 = 108028^2 + 14885^2 .

It is a cyclic number.

It is not a de Polignac number, because 11891612009 - 2²⁸ = 11623176553 is a prime.

Together with 11891612011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11891612209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5945806004 + 5945806005.

It is an arithmetic number, because the mean of its divisors is an integer number (5945806005).

Almost surely, 2^11891612009 is an apocalyptic number.

It is an amenable number.

11891612009 is a deficient number, since it is larger than the sum of its proper divisors (1).

11891612009 is an equidigital number, since it uses as much as digits as its factorization.

11891612009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 38.

The spelling of 11891612009 in words is "eleven billion, eight hundred ninety-one million, six hundred twelve thousand, nine".