11911210991 has 2 divisors, whose sum is σ = 11911210992. Its totient is φ = 11911210990.

The previous prime is 11911210957. The next prime is 11911210999. The reversal of 11911210991 is 19901211911.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11911210991 - 2¹⁰ = 11911209967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11911210999) 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 as a sum of consecutive naturals, namely, 5955605495 + 5955605496.

It is an arithmetic number, because the mean of its divisors is an integer number (5955605496).

Almost surely, 2^11911210991 is an apocalyptic number.

11911210991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11911210991 is an equidigital number, since it uses as much as digits as its factorization.

11911210991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 35.

The spelling of 11911210991 in words is "eleven billion, nine hundred eleven million, two hundred ten thousand, nine hundred ninety-one".