331221312 has 140 divisors (see below), whose sum is σ = 990065076. Its totient is φ = 109486080.

The previous prime is 331221307. The next prime is 331221337. The reversal of 331221312 is 213122133.

331221312 is a `hidden beast` number, since 331 + 2 + 21 + 312 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 49787136 + 281434176 = 7056^2 + 16776^2 .

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 938128 + ... + 938480.

Almost surely, 2^331221312 is an apocalyptic number.

331221312 is a gapful number since it is divisible by the number (32) 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 331221312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (495032538).

331221312 is an abundant number, since it is smaller than the sum of its proper divisors (658843764).

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

331221312 is a wasteful number, since it uses less digits than its factorization.

331221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558 (or 539 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 331221312 is about 18199.4865861650. The cubic root of 331221312 is about 691.8937767835.

Adding to 331221312 its reverse (213122133), we get a palindrome (544343445).

It can be divided in two parts, 33122131 and 2, that added together give a palindrome (33122133).

The spelling of 331221312 in words is "three hundred thirty-one million, two hundred twenty-one thousand, three hundred twelve".