2011021021991 has 2 divisors, whose sum is σ = 2011021021992. Its totient is φ = 2011021021990.

The previous prime is 2011021021987. The next prime is 2011021022009. The reversal of 2011021021991 is 1991201201102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2011021021991 - 2² = 2011021021987 is a prime.

It is a super-2 number, since 2×2011021021991² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2011021021931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1005510510995 + 1005510510996.

It is an arithmetic number, because the mean of its divisors is an integer number (1005510510996).

Almost surely, 2^{2011021021991} is an apocalyptic number.

2011021021991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2011021021991 is an equidigital number, since it uses as much as digits as its factorization.

2011021021991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 29.

The spelling of 2011021021991 in words is "two trillion, eleven billion, twenty-one million, twenty-one thousand, nine hundred ninety-one".