11211111219991 has 2 divisors, whose sum is σ = 11211111219992. Its totient is φ = 11211111219990.

The previous prime is 11211111219989. The next prime is 11211111220021. The reversal of 11211111219991 is 19991211111211.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11211111219991 - 2¹ = 11211111219989 is a prime.

Together with 11211111219989, 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 (11211111219941) 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, 5605555609995 + 5605555609996.

It is an arithmetic number, because the mean of its divisors is an integer number (5605555609996).

Almost surely, 2^{11211111219991} is an apocalyptic number.

11211111219991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11211111219991 is an equidigital number, since it uses as much as digits as its factorization.

11211111219991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 40.

The spelling of 11211111219991 in words is "eleven trillion, two hundred eleven billion, one hundred eleven million, two hundred nineteen thousand, nine hundred ninety-one".