111211221222181 has 2 divisors, whose sum is σ = 111211221222182. Its totient is φ = 111211221222180.

The previous prime is 111211221222149. The next prime is 111211221222203. The reversal of 111211221222181 is 181222122112111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68985150832900 + 42226070389281 = 8305730^2 + 6498159^2 .

It is a cyclic number.

It is not a de Polignac number, because 111211221222181 - 2⁵ = 111211221222149 is a prime.

It is a super-2 number, since 2×111211221222181² (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 (111211221222581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55605610611090 + 55605610611091.

It is an arithmetic number, because the mean of its divisors is an integer number (55605610611091).

Almost surely, 2^{111211221222181} is an apocalyptic number.

It is an amenable number.

111211221222181 is a deficient number, since it is larger than the sum of its proper divisors (1).

111211221222181 is an equidigital number, since it uses as much as digits as its factorization.

111211221222181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 512, while the sum is 28.

Adding to 111211221222181 its reverse (181222122112111), we get a palindrome (292433343334292).

The spelling of 111211221222181 in words is "one hundred eleven trillion, two hundred eleven billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred eighty-one".