1321222221 has 12 divisors (see below), whose sum is σ = 2081926080. Its totient is φ = 800740680.

The previous prime is 1321222219. The next prime is 1321222237. The reversal of 1321222221 is 1222221231.

It is not a de Polignac number, because 1321222221 - 2¹ = 1321222219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321222194 and 1321222203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321222211) 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 11 ways as a sum of consecutive naturals, for example, 6672741 + ... + 6672938.

It is an arithmetic number, because the mean of its divisors is an integer number (173493840).

Almost surely, 2^1321222221 is an apocalyptic number.

1321222221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321222221 is a deficient number, since it is larger than the sum of its proper divisors (760703859).

1321222221 is a wasteful number, since it uses less digits than its factorization.

1321222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13345696 (or 13345693 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 1321222221 is about 36348.6206203207. The cubic root of 1321222221 is about 1097.2997740112.

Adding to 1321222221 its reverse (1222221231), we get a palindrome (2543443452).

The spelling of 1321222221 in words is "one billion, three hundred twenty-one million, two hundred twenty-two thousand, two hundred twenty-one".