13221131220 has 144 divisors (see below), whose sum is σ = 43851592512. Its totient is φ = 3197675520.

The previous prime is 13221131219. The next prime is 13221131237. The reversal of 13221131220 is 2213112231.

13221131220 is a `hidden beast` number, since 1 + 322 + 11 + 312 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 13221131193 and 13221131202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 869604 + ... + 884676.

It is an arithmetic number, because the mean of its divisors is an integer number (304524948).

Almost surely, 2^13221131220 is an apocalyptic number.

13221131220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 13221131220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21925796256).

13221131220 is an abundant number, since it is smaller than the sum of its proper divisors (30630461292).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13221131220 is a wasteful number, since it uses less digits than its factorization.

13221131220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15542 (or 15537 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 13221131220 its reverse (2213112231), we get a palindrome (15434243451).

It can be divided in two parts, 13221 and 131220, that added together give a palindrome (144441).

The spelling of 13221131220 in words is "thirteen billion, two hundred twenty-one million, one hundred thirty-one thousand, two hundred twenty".