222221221 has 2 divisors, whose sum is σ = 222221222. Its totient is φ = 222221220.

The previous prime is 222221201. The next prime is 222221227. The reversal of 222221221 is 122122222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179828100 + 42393121 = 13410^2 + 6511^2 .

It is a cyclic number.

It is not a de Polignac number, because 222221221 - 2²⁷ = 88003493 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 222221195 and 222221204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (222221227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 111110610 + 111110611.

It is an arithmetic number, because the mean of its divisors is an integer number (111110611).

Almost surely, 2^222221221 is an apocalyptic number.

It is an amenable number.

222221221 is a deficient number, since it is larger than the sum of its proper divisors (1).

222221221 is an equidigital number, since it uses as much as digits as its factorization.

222221221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 16.

The square root of 222221221 is about 14907.0862679465. The cubic root of 222221221 is about 605.7059546053.

Adding to 222221221 its reverse (122122222), we get a palindrome (344343443).

The spelling of 222221221 in words is "two hundred twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".