11111109999991 has 2 divisors, whose sum is σ = 11111109999992. Its totient is φ = 11111109999990.

The previous prime is 11111109999959. The next prime is 11111110000009. The reversal of 11111109999991 is 19999990111111.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11111109999991 - 2⁵ = 11111109999959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11111109999391) 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, 5555554999995 + 5555554999996.

It is an arithmetic number, because the mean of its divisors is an integer number (5555554999996).

Almost surely, 2^{11111109999991} is an apocalyptic number.

11111109999991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111109999991 is an equidigital number, since it uses as much as digits as its factorization.

11111109999991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 531441, while the sum is 61.

The spelling of 11111109999991 in words is "eleven trillion, one hundred eleven billion, one hundred nine million, nine hundred ninety-nine thousand, nine hundred ninety-one".