201111001991 has 2 divisors, whose sum is σ = 201111001992. Its totient is φ = 201111001990.

The previous prime is 201111001921. The next prime is 201111002023. The reversal of 201111001991 is 199100111102.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201111001991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 201111001991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201111001921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100555500995 + 100555500996.

It is an arithmetic number, because the mean of its divisors is an integer number (100555500996).

Almost surely, 2^201111001991 is an apocalyptic number.

201111001991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201111001991 is an equidigital number, since it uses as much as digits as its factorization.

201111001991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 26.

The spelling of 201111001991 in words is "two hundred one billion, one hundred eleven million, one thousand, nine hundred ninety-one".