222111221 has 4 divisors (see below), whose sum is σ = 224310444. Its totient is φ = 219912000.

The previous prime is 222111209. The next prime is 222111233. The reversal of 222111221 is 122111222.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (222111209) and next prime (222111233).

It can be written as a sum of positive squares in 2 ways, for example, as 182547121 + 39564100 = 13511^2 + 6290^2 .

It is a cyclic number.

It is not a de Polignac number, because 222111221 - 2¹⁴ = 222094837 is a prime.

It is a super-2 number, since 2×222111221² = 98666788988221682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 222111196 and 222111205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (222111251) 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 in 3 ways as a sum of consecutive naturals, for example, 1099460 + ... + 1099661.

It is an arithmetic number, because the mean of its divisors is an integer number (56077611).

Almost surely, 2^222111221 is an apocalyptic number.

It is an amenable number.

222111221 is a deficient number, since it is larger than the sum of its proper divisors (2199223).

222111221 is a wasteful number, since it uses less digits than its factorization.

222111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2199222.

The product of its digits is 32, while the sum is 14.

The square root of 222111221 is about 14903.3962907788. The cubic root of 222111221 is about 605.6059961774.

Adding to 222111221 its reverse (122111222), we get a palindrome (344222443).

Subtracting from 222111221 its reverse (122111222), we obtain a palindrome (99999999).

It can be divided in two parts, 22211 and 1221, that added together give a palindrome (23432).

The spelling of 222111221 in words is "two hundred twenty-two million, one hundred eleven thousand, two hundred twenty-one".