13220312221 has 4 divisors (see below), whose sum is σ = 13221309244. Its totient is φ = 13219315200.

The previous prime is 13220312213. The next prime is 13220312227. The reversal of 13220312221 is 12221302231.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8318352025 + 4901960196 = 91205^2 + 70014^2 .

It is a cyclic number.

It is not a de Polignac number, because 13220312221 - 2³ = 13220312213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13220312227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 478350 + ... + 505231.

It is an arithmetic number, because the mean of its divisors is an integer number (3305327311).

Almost surely, 2^13220312221 is an apocalyptic number.

It is an amenable number.

13220312221 is a deficient number, since it is larger than the sum of its proper divisors (997023).

13220312221 is an equidigital number, since it uses as much as digits as its factorization.

13220312221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997022.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 13220312221 its reverse (12221302231), we get a palindrome (25441614452).

The spelling of 13220312221 in words is "thirteen billion, two hundred twenty million, three hundred twelve thousand, two hundred twenty-one".