222181221 has 4 divisors (see below), whose sum is σ = 296241632. Its totient is φ = 148120812.

The previous prime is 222181217. The next prime is 222181229. The reversal of 222181221 is 122181222.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 222181221 - 2² = 222181217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (222181229) 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, 37030201 + ... + 37030206.

It is an arithmetic number, because the mean of its divisors is an integer number (74060408).

Almost surely, 2^222181221 is an apocalyptic number.

It is an amenable number.

222181221 is a deficient number, since it is larger than the sum of its proper divisors (74060411).

222181221 is an equidigital number, since it uses as much as digits as its factorization.

222181221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74060410.

The product of its digits is 256, while the sum is 21.

The square root of 222181221 is about 14905.7445637580. The cubic root of 222181221 is about 605.6696099035.

Subtracting from 222181221 its reverse (122181222), we obtain a palindrome (99999999).

The spelling of 222181221 in words is "two hundred twenty-two million, one hundred eighty-one thousand, two hundred twenty-one".