22223221 has 4 divisors (see below), whose sum is σ = 23189472.
Its totient is φ = 21256972.
The previous prime is 22223219. The next prime is 22223231. The reversal of 22223221 is 12232222.
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 an emirpimes, since its reverse is a distinct semiprime: 12232222 = 2 ⋅6116111.
It is a cyclic number.
It is not a de Polignac number, because 22223221 - 21 = 22223219 is a prime.
It is a super-2 number, since 2×222232212 = 987743103229682, 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 = 22223195 and 22223204.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (22223231) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 483091 + ... + 483136.
It is an arithmetic number, because the mean of its divisors is an integer number (5797368).
Almost surely, 222223221 is an apocalyptic number.
It is an amenable number.
22223221 is a deficient number, since it is larger than the sum of its proper divisors (966251).
22223221 is an equidigital number, since it uses as much as digits as its factorization.
22223221 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 966250.
The product of its digits is 192, while the sum is 16.
The square root of 22223221 is about 4714.1511431010.
The cubic root of 22223221 is about 281.1484337132.
Adding to 22223221 its reverse (12232222), we get a palindrome (34455443).
Subtracting from 22223221 its reverse (12232222), we obtain a palindrome (9990999).
The spelling of 22223221 in words is "twenty-two million, two hundred twenty-three thousand, two hundred twenty-one".