1001121009991 has 2 divisors, whose sum is σ = 1001121009992. Its totient is φ = 1001121009990.

The previous prime is 1001121009989. The next prime is 1001121010003. The reversal of 1001121009991 is 1999001211001.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1001121009991 - 2¹ = 1001121009989 is a prime.

Together with 1001121009989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001121009961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500560504995 + 500560504996.

It is an arithmetic number, because the mean of its divisors is an integer number (500560504996).

Almost surely, 2^{1001121009991} is an apocalyptic number.

1001121009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001121009991 is an equidigital number, since it uses as much as digits as its factorization.

1001121009991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 34.

The spelling of 1001121009991 in words is "one trillion, one billion, one hundred twenty-one million, nine thousand, nine hundred ninety-one".