111111220009991 has 2 divisors, whose sum is σ = 111111220009992. Its totient is φ = 111111220009990.

The previous prime is 111111220009963. The next prime is 111111220010017. The reversal of 111111220009991 is 199900022111111.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 111111220009991 - 2¹⁰ = 111111220008967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111220009931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555610004995 + 55555610004996.

It is an arithmetic number, because the mean of its divisors is an integer number (55555610004996).

Almost surely, 2^{111111220009991} is an apocalyptic number.

111111220009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111220009991 is an equidigital number, since it uses as much as digits as its factorization.

111111220009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 38.

The spelling of 111111220009991 in words is "one hundred eleven trillion, one hundred eleven billion, two hundred twenty million, nine thousand, nine hundred ninety-one".