22431221 has 4 divisors (see below), whose sum is σ = 22738572. Its totient is φ = 22123872.

The previous prime is 22431209. The next prime is 22431263. The reversal of 22431221 is 12213422.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19140625 + 3290596 = 4375^2 + 1814^2 .

It is a cyclic number.

It is not a de Polignac number, because 22431221 - 2¹⁰ = 22430197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 22431221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22431271) 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, 153566 + ... + 153711.

It is an arithmetic number, because the mean of its divisors is an integer number (5684643).

Almost surely, 2^22431221 is an apocalyptic number.

It is an amenable number.

22431221 is a deficient number, since it is larger than the sum of its proper divisors (307351).

22431221 is an equidigital number, since it uses as much as digits as its factorization.

22431221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307350.

The product of its digits is 192, while the sum is 17.

The square root of 22431221 is about 4736.1609981081. The cubic root of 22431221 is about 282.0228549791.

Adding to 22431221 its reverse (12213422), we get a palindrome (34644643).

The spelling of 22431221 in words is "twenty-two million, four hundred thirty-one thousand, two hundred twenty-one".