22221121 has 4 divisors (see below), whose sum is σ = 23930452. Its totient is φ = 20511792.

The previous prime is 22221109. The next prime is 22221161. The reversal of 22221121 is 12112222.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12112222 = 2 ⋅6056111.

It can be written as a sum of positive squares in 2 ways, for example, as 1290496 + 20930625 = 1136^2 + 4575^2 .

It is a cyclic number.

It is not a de Polignac number, because 22221121 - 2¹¹ = 22219073 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1709317 = 22221121 / (2 + 2 + 2 + 2 + 1 + 1 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (22221161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 854646 + ... + 854671.

It is an arithmetic number, because the mean of its divisors is an integer number (5982613).

Almost surely, 2^22221121 is an apocalyptic number.

It is an amenable number.

22221121 is a deficient number, since it is larger than the sum of its proper divisors (1709331).

22221121 is a wasteful number, since it uses less digits than its factorization.

22221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1709330.

The product of its digits is 32, while the sum is 13.

The square root of 22221121 is about 4713.9284042081. The cubic root of 22221121 is about 281.1395776566.

Adding to 22221121 its reverse (12112222), we get a palindrome (34333343).

The spelling of 22221121 in words is "twenty-two million, two hundred twenty-one thousand, one hundred twenty-one".