111000000009991 has 2 divisors, whose sum is σ = 111000000009992. Its totient is φ = 111000000009990.

The previous prime is 111000000009841. The next prime is 111000000010037. The reversal of 111000000009991 is 199900000000111.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 111000000009991 - 2¹⁷ = 110999999878919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111000000006991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55500000004995 + 55500000004996.

It is an arithmetic number, because the mean of its divisors is an integer number (55500000004996).

Almost surely, 2^{111000000009991} is an apocalyptic number.

111000000009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

111000000009991 is an equidigital number, since it uses as much as digits as its factorization.

111000000009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 729, while the sum is 31.

The spelling of 111000000009991 in words is "one hundred eleven trillion, nine thousand, nine hundred ninety-one".