Adding to 222221 its reverse (122222), we get a palindrome (344443).
Subtracting from 222221 its reverse (122222), we obtain a palindrome (99999).
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, and also a brilliant number, because the two primes have the same length.
It is a cyclic number.
It is a Duffinian number.
It is a Curzon number.
It is a nialpdrome in base 10.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 222221.
2222221 is an apocalyptic number.
It is an amenable number.
222221 is an equidigital number, since it uses as much as digits as its factorization.
222221 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 978.
The square root of 222221 is about 471.4032244268. The cubic root of 222221 is about 60.5705753813.
The spelling of 222221 in words is "two hundred twenty-two thousand, two hundred twenty-one", and thus it is an iban number.