22131221 has 16 divisors (see below), whose sum is σ = 26673408. Its totient is φ = 17952000.

The previous prime is 22131211. The next prime is 22131223. The reversal of 22131221 is 12213122.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 22131221 - 2¹⁸ = 21869077 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 22131196 and 22131205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22131223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15581 + ... + 16941.

It is an arithmetic number, because the mean of its divisors is an integer number (1667088).

Almost surely, 2^22131221 is an apocalyptic number.

It is an amenable number.

22131221 is a deficient number, since it is larger than the sum of its proper divisors (4542187).

22131221 is a wasteful number, since it uses less digits than its factorization.

22131221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1492.

The product of its digits is 48, while the sum is 14.

The square root of 22131221 is about 4704.3831689181. The cubic root of 22131221 is about 280.7599297062.

Adding to 22131221 its reverse (12213122), we get a palindrome (34344343).

The spelling of 22131221 in words is "twenty-two million, one hundred thirty-one thousand, two hundred twenty-one".