1020111109991 has 2 divisors, whose sum is σ = 1020111109992. Its totient is φ = 1020111109990.

The previous prime is 1020111109987. The next prime is 1020111109993. The reversal of 1020111109991 is 1999011110201.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1020111109991 - 2² = 1020111109987 is a prime.

Together with 1020111109993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020111109993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510055554995 + 510055554996.

It is an arithmetic number, because the mean of its divisors is an integer number (510055554996).

Almost surely, 2^{1020111109991} is an apocalyptic number.

1020111109991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020111109991 is an equidigital number, since it uses as much as digits as its factorization.

1020111109991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 35.

The spelling of 1020111109991 in words is "one trillion, twenty billion, one hundred eleven million, one hundred nine thousand, nine hundred ninety-one".