11211222991 has 2 divisors, whose sum is σ = 11211222992. Its totient is φ = 11211222990.

The previous prime is 11211222989. The next prime is 11211223003. The reversal of 11211222991 is 19922211211.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11211222991 - 2¹ = 11211222989 is a prime.

Together with 11211222989, 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 (11211222931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5605611495 + 5605611496.

It is an arithmetic number, because the mean of its divisors is an integer number (5605611496).

Almost surely, 2^11211222991 is an apocalyptic number.

11211222991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11211222991 is an equidigital number, since it uses as much as digits as its factorization.

11211222991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 31.

The spelling of 11211222991 in words is "eleven billion, two hundred eleven million, two hundred twenty-two thousand, nine hundred ninety-one".