13121232221 has 2 divisors, whose sum is σ = 13121232222. Its totient is φ = 13121232220.

The previous prime is 13121232217. The next prime is 13121232233. The reversal of 13121232221 is 12223212131.

13121232221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8275540900 + 4845691321 = 90970^2 + 69611^2 .

It is a cyclic number.

It is not a de Polignac number, because 13121232221 - 2² = 13121232217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 13121232193 and 13121232202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13121232821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6560616110 + 6560616111.

It is an arithmetic number, because the mean of its divisors is an integer number (6560616111).

Almost surely, 2^13121232221 is an apocalyptic number.

It is an amenable number.

13121232221 is a deficient number, since it is larger than the sum of its proper divisors (1).

13121232221 is an equidigital number, since it uses as much as digits as its factorization.

13121232221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 20.

Adding to 13121232221 its reverse (12223212131), we get a palindrome (25344444352).

The spelling of 13121232221 in words is "thirteen billion, one hundred twenty-one million, two hundred thirty-two thousand, two hundred twenty-one".