1211122009991 has 2 divisors, whose sum is σ = 1211122009992. Its totient is φ = 1211122009990.

The previous prime is 1211122009957. The next prime is 1211122010069. The reversal of 1211122009991 is 1999002211121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211122009991 - 2¹⁴ = 1211121993607 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211122008991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605561004995 + 605561004996.

It is an arithmetic number, because the mean of its divisors is an integer number (605561004996).

Almost surely, 2^{1211122009991} is an apocalyptic number.

1211122009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211122009991 is an equidigital number, since it uses as much as digits as its factorization.

1211122009991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 38.

The spelling of 1211122009991 in words is "one trillion, two hundred eleven billion, one hundred twenty-two million, nine thousand, nine hundred ninety-one".