111212222112221 has 2 divisors, whose sum is σ = 111212222112222. Its totient is φ = 111212222112220.

The previous prime is 111212222112197. The next prime is 111212222112223. The reversal of 111212222112221 is 122211222212111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111211472119225 + 749992996 = 10545685^2 + 27386^2 .

It is an emirp because it is prime and its reverse (122211222212111) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 111212222112221 - 2¹⁰ = 111212222111197 is a prime.

Together with 111212222112223, 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 (111212222112223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55606111056110 + 55606111056111.

It is an arithmetic number, because the mean of its divisors is an integer number (55606111056111).

Almost surely, 2^{111212222112221} is an apocalyptic number.

It is an amenable number.

111212222112221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111212222112221 is an equidigital number, since it uses as much as digits as its factorization.

111212222112221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 256, while the sum is 23.

Adding to 111212222112221 its reverse (122211222212111), we get a palindrome (233423444324332).

The spelling of 111212222112221 in words is "one hundred eleven trillion, two hundred twelve billion, two hundred twenty-two million, one hundred twelve thousand, two hundred twenty-one".