1001122011991 has 2 divisors, whose sum is σ = 1001122011992. Its totient is φ = 1001122011990.

The previous prime is 1001122011961. The next prime is 1001122012001. The reversal of 1001122011991 is 1991102211001.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1001122011991 - 2⁵ = 1001122011959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001122011941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500561005995 + 500561005996.

It is an arithmetic number, because the mean of its divisors is an integer number (500561005996).

Almost surely, 2^{1001122011991} is an apocalyptic number.

1001122011991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001122011991 is an equidigital number, since it uses as much as digits as its factorization.

1001122011991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 28.

Adding to 1001122011991 its reverse (1991102211001), we get a palindrome (2992224222992).

The spelling of 1001122011991 in words is "one trillion, one billion, one hundred twenty-two million, eleven thousand, nine hundred ninety-one".