1321211221 has 12 divisors (see below), whose sum is σ = 1455479116. Its totient is φ = 1198422720.

The previous prime is 1321211209. The next prime is 1321211231. The reversal of 1321211221 is 1221121231.

It can be written as a sum of positive squares in 2 ways, for example, as 1181640625 + 139570596 = 34375^2 + 11814^2 .

It is not a de Polignac number, because 1321211221 - 2⁷ = 1321211093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1321211195 and 1321211204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321211201) 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 11 ways as a sum of consecutive naturals, for example, 43351 + ... + 67243.

Almost surely, 2^1321211221 is an apocalyptic number.

1321211221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321211221 is a deficient number, since it is larger than the sum of its proper divisors (134267895).

1321211221 is a wasteful number, since it uses less digits than its factorization.

1321211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24372 (or 24361 counting only the distinct ones).

The product of its digits is 48, while the sum is 16.

The square root of 1321211221 is about 36348.4693075238. The cubic root of 1321211221 is about 1097.2967287675.

Adding to 1321211221 its reverse (1221121231), we get a palindrome (2542332452).

The spelling of 1321211221 in words is "one billion, three hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".