13121223221 has 8 divisors (see below), whose sum is σ = 13169818200. Its totient is φ = 13072711680.

The previous prime is 13121223187. The next prime is 13121223223. The reversal of 13121223221 is 12232212131.

It can be written as a sum of positive squares in 4 ways, for example, as 853224100 + 12267999121 = 29210^2 + 110761^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13121223221 - 2¹⁰ = 13121222197 is a prime.

It is a super-2 number, since 2×13121223221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13121223193 and 13121223202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121223223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 303485 + ... + 344013.

It is an arithmetic number, because the mean of its divisors is an integer number (1646227275).

Almost surely, 2^13121223221 is an apocalyptic number.

It is an amenable number.

13121223221 is a deficient number, since it is larger than the sum of its proper divisors (48594979).

13121223221 is an equidigital number, since it uses as much as digits as its factorization.

13121223221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41719.

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

Adding to 13121223221 its reverse (12232212131), we get a palindrome (25353435352).

The spelling of 13121223221 in words is "thirteen billion, one hundred twenty-one million, two hundred twenty-three thousand, two hundred twenty-one".