111121212221 has 2 divisors, whose sum is σ = 111121212222. Its totient is φ = 111121212220.

The previous prime is 111121212203. The next prime is 111121212253. The reversal of 111121212221 is 122212121111.

It is a m-pointer prime, because the next prime (111121212253) can be obtained adding 111121212221 to its product of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 92899992025 + 18221220196 = 304795^2 + 134986^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111121212221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 111121212221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111121212271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55560606110 + 55560606111.

It is an arithmetic number, because the mean of its divisors is an integer number (55560606111).

Almost surely, 2^111121212221 is an apocalyptic number.

It is an amenable number.

111121212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111121212221 is an equidigital number, since it uses as much as digits as its factorization.

111121212221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32, while the sum is 17.

Adding to 111121212221 its reverse (122212121111), we get a palindrome (233333333332).

The spelling of 111121212221 in words is "one hundred eleven billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".