331121220 has 24 divisors (see below), whose sum is σ = 927139584. Its totient is φ = 88298976.

The previous prime is 331121143. The next prime is 331121221. The reversal of 331121220 is 22121133.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 331121220.

It is not an unprimeable number, because it can be changed into a prime (331121221) 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, 2759284 + ... + 2759403.

It is an arithmetic number, because the mean of its divisors is an integer number (38630816).

Almost surely, 2^331121220 is an apocalyptic number.

331121220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

331121220 is an abundant number, since it is smaller than the sum of its proper divisors (596018364).

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

331121220 is a wasteful number, since it uses less digits than its factorization.

331121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5518699 (or 5518697 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 331121220 is about 18196.7365205962. The cubic root of 331121220 is about 691.8240751404.

Adding to 331121220 its reverse (22121133), we get a palindrome (353242353).

It can be divided in two parts, 3311 and 21220, that added together give a triangular number (24531 = T₂₂₁).

The spelling of 331121220 in words is "three hundred thirty-one million, one hundred twenty-one thousand, two hundred twenty".