12001001011991 has 2 divisors, whose sum is σ = 12001001011992. Its totient is φ = 12001001011990.

The previous prime is 12001001011913. The next prime is 12001001012023. The reversal of 12001001011991 is 19911010010021.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12001001011991 is a prime.

It is a super-2 number, since 2×12001001011991² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 12001001011991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12001001011091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6000500505995 + 6000500505996.

It is an arithmetic number, because the mean of its divisors is an integer number (6000500505996).

Almost surely, 2^{12001001011991} is an apocalyptic number.

12001001011991 is a deficient number, since it is larger than the sum of its proper divisors (1).

12001001011991 is an equidigital number, since it uses as much as digits as its factorization.

12001001011991 is an evil number, because the sum of its binary digits is even.

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

The spelling of 12001001011991 in words is "twelve trillion, one billion, one million, eleven thousand, nine hundred ninety-one".