221222111221 has 2 divisors, whose sum is σ = 221222111222. Its totient is φ = 221222111220.

The previous prime is 221222111197. The next prime is 221222111293. The reversal of 221222111221 is 122111222122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 205833708721 + 15388402500 = 453689^2 + 124050^2 .

It is a cyclic number.

It is not a de Polignac number, because 221222111221 - 2⁷ = 221222111093 is a prime.

It is a super-2 number, since 2×221222111221² (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 (221222111921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110611055610 + 110611055611.

It is an arithmetic number, because the mean of its divisors is an integer number (110611055611).

Almost surely, 2^221222111221 is an apocalyptic number.

It is an amenable number.

221222111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221222111221 is an equidigital number, since it uses as much as digits as its factorization.

221222111221 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 221222111221 its reverse (122111222122), we get a palindrome (343333333343).

The spelling of 221222111221 in words is "two hundred twenty-one billion, two hundred twenty-two million, one hundred eleven thousand, two hundred twenty-one".