111221222221 has 2 divisors, whose sum is σ = 111221222222. Its totient is φ = 111221222220.

The previous prime is 111221222219. The next prime is 111221222239. The reversal of 111221222221 is 122222122111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93872380996 + 17348841225 = 306386^2 + 131715^2 .

It is a cyclic number.

It is not a de Polignac number, because 111221222221 - 2¹ = 111221222219 is a prime.

Together with 111221222219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111221222261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55610611110 + 55610611111.

It is an arithmetic number, because the mean of its divisors is an integer number (55610611111).

Almost surely, 2^111221222221 is an apocalyptic number.

It is an amenable number.

111221222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111221222221 is an equidigital number, since it uses as much as digits as its factorization.

111221222221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128, while the sum is 19.

Adding to 111221222221 its reverse (122222122111), we get a palindrome (233443344332).

The spelling of 111221222221 in words is "one hundred eleven billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty-one".