11221211891 has 2 divisors, whose sum is σ = 11221211892. Its totient is φ = 11221211890.

The previous prime is 11221211849. The next prime is 11221211893. The reversal of 11221211891 is 19811212211.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11221211891 is a prime.

Together with 11221211893, 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 (11221211893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5610605945 + 5610605946.

It is an arithmetic number, because the mean of its divisors is an integer number (5610605946).

Almost surely, 2^11221211891 is an apocalyptic number.

11221211891 is a deficient number, since it is larger than the sum of its proper divisors (1).

11221211891 is an equidigital number, since it uses as much as digits as its factorization.

11221211891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 29.

The spelling of 11221211891 in words is "eleven billion, two hundred twenty-one million, two hundred eleven thousand, eight hundred ninety-one".