121010111101991 has 2 divisors, whose sum is σ = 121010111101992. Its totient is φ = 121010111101990.

The previous prime is 121010111101883. The next prime is 121010111102003. The reversal of 121010111101991 is 199101111010121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121010111101991 - 2¹⁸ = 121010110839847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121010111103991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60505055550995 + 60505055550996.

It is an arithmetic number, because the mean of its divisors is an integer number (60505055550996).

Almost surely, 2^{121010111101991} is an apocalyptic number.

121010111101991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121010111101991 is an equidigital number, since it uses as much as digits as its factorization.

121010111101991 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 29.

The spelling of 121010111101991 in words is "one hundred twenty-one trillion, ten billion, one hundred eleven million, one hundred one thousand, nine hundred ninety-one".