2331221220 has 144 divisors (see below), whose sum is σ = 7539058800. Its totient is φ = 581050368.

The previous prime is 2331221213. The next prime is 2331221227. The reversal of 2331221220 is 221221332.

It is an interprime number because it is at equal distance from previous prime (2331221213) and next prime (2331221227).

It can be written as a sum of positive squares in 8 ways, for example, as 505710144 + 1825511076 = 22488^2 + 42726^2 .

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 = 2331221193 and 2331221202.

It is not an unprimeable number, because it can be changed into a prime (2331221227) 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 47 ways as a sum of consecutive naturals, for example, 453384 + ... + 458496.

It is an arithmetic number, because the mean of its divisors is an integer number (52354575).

Almost surely, 2^2331221220 is an apocalyptic number.

2331221220 is a gapful number since it is divisible by the number (20) 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 2331221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3769529400).

2331221220 is an abundant number, since it is smaller than the sum of its proper divisors (5207837580).

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

2331221220 is a wasteful number, since it uses less digits than its factorization.

2331221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5294 (or 5289 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 2331221220 is about 48282.7217542673. The cubic root of 2331221220 is about 1325.9520808765.

Adding to 2331221220 its reverse (221221332), we get a palindrome (2552442552).

The spelling of 2331221220 in words is "two billion, three hundred thirty-one million, two hundred twenty-one thousand, two hundred twenty".