331221220 has 96 divisors (see below), whose sum is σ = 784982016. Its totient is φ = 116361600.

The previous prime is 331221203. The next prime is 331221239. The reversal of 331221220 is 22122133.

It is a junction number, because it is equal to n+sod(n) for n = 331221194 and 331221203.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1064865 + ... + 1065175.

It is an arithmetic number, because the mean of its divisors is an integer number (8176896).

Almost surely, 2^331221220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 331221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (392491008).

331221220 is an abundant number, since it is smaller than the sum of its proper divisors (453760796).

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

331221220 is a wasteful number, since it uses less digits than its factorization.

331221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 331221220 is about 18199.4840586210. The cubic root of 331221220 is about 691.8937127233.

Adding to 331221220 its reverse (22122133), we get a palindrome (353343353).

The spelling of 331221220 in words is "three hundred thirty-one million, two hundred twenty-one thousand, two hundred twenty".