10122111991 has 2 divisors, whose sum is σ = 10122111992. Its totient is φ = 10122111990.

The previous prime is 10122111959. The next prime is 10122112109. The reversal of 10122111991 is 19911122101.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 10122111991 - 2⁵ = 10122111959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10122111931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5061055995 + 5061055996.

It is an arithmetic number, because the mean of its divisors is an integer number (5061055996).

Almost surely, 2^10122111991 is an apocalyptic number.

10122111991 is a deficient number, since it is larger than the sum of its proper divisors (1).

10122111991 is an equidigital number, since it uses as much as digits as its factorization.

10122111991 is an odious number, because the sum of its binary digits is odd.

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

The spelling of 10122111991 in words is "ten billion, one hundred twenty-two million, one hundred eleven thousand, nine hundred ninety-one".