111021211981 has 2 divisors, whose sum is σ = 111021211982. Its totient is φ = 111021211980.

The previous prime is 111021211957. The next prime is 111021212011. The reversal of 111021211981 is 189112120111.

111021211981 is nontrivially palindromic in base 12.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67659813225 + 43361398756 = 260115^2 + 208234^2 .

It is a cyclic number.

It is not a de Polignac number, because 111021211981 - 2⁵ = 111021211949 is a prime.

It is a super-2 number, since 2×111021211981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111021211921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55510605990 + 55510605991.

It is an arithmetic number, because the mean of its divisors is an integer number (55510605991).

Almost surely, 2^111021211981 is an apocalyptic number.

It is an amenable number.

111021211981 is a deficient number, since it is larger than the sum of its proper divisors (1).

111021211981 is an equidigital number, since it uses as much as digits as its factorization.

111021211981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 28.

The spelling of 111021211981 in words is "one hundred eleven billion, twenty-one million, two hundred eleven thousand, nine hundred eighty-one".