13220121221 has 16 divisors (see below), whose sum is σ = 14019672240. Its totient is φ = 12443934720.

The previous prime is 13220121149. The next prime is 13220121241. The reversal of 13220121221 is 12212102231.

13220121221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 75498721 + 13144622500 = 8689^2 + 114650^2 .

It is a cyclic number.

It is not a de Polignac number, because 13220121221 - 2¹⁰ = 13220120197 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 13220121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13220121241) 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 in 15 ways as a sum of consecutive naturals, for example, 2109725 + ... + 2115981.

It is an arithmetic number, because the mean of its divisors is an integer number (876229515).

Almost surely, 2^13220121221 is an apocalyptic number.

It is an amenable number.

13220121221 is a deficient number, since it is larger than the sum of its proper divisors (799551019).

13220121221 is a wasteful number, since it uses less digits than its factorization.

13220121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8104.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 13220121221 its reverse (12212102231), we get a palindrome (25432223452).

The spelling of 13220121221 in words is "thirteen billion, two hundred twenty million, one hundred twenty-one thousand, two hundred twenty-one".