111100220121991 has 2 divisors, whose sum is σ = 111100220121992. Its totient is φ = 111100220121990.

The previous prime is 111100220121953. The next prime is 111100220122049. The reversal of 111100220121991 is 199121022001111.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 111100220121991 - 2²³ = 111100211733383 is a prime.

It is a super-2 number, since 2×111100220121991² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111100220161991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55550110060995 + 55550110060996.

It is an arithmetic number, because the mean of its divisors is an integer number (55550110060996).

Almost surely, 2^{111100220121991} is an apocalyptic number.

111100220121991 is a deficient number, since it is larger than the sum of its proper divisors (1).

111100220121991 is an equidigital number, since it uses as much as digits as its factorization.

111100220121991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 31.

The spelling of 111100220121991 in words is "one hundred eleven trillion, one hundred billion, two hundred twenty million, one hundred twenty-one thousand, nine hundred ninety-one".