331218 has 12 divisors (see below), whose sum is σ = 717678. Its totient is φ = 110400.

The previous prime is 331217. The next prime is 331231. The reversal of 331218 is 812133.

It can be written as a sum of positive squares in only one way, i.e., 288369 + 42849 = 537^2 + 207^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 18401 = 331218 / (3 + 3 + 1 + 2 + 1 + 8).

It is a nialpdrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 331218.

It is not an unprimeable number, because it can be changed into a prime (331213) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9183 + ... + 9218.

2³³¹²¹⁸ is an apocalyptic number.

331218 is an abundant number, since it is smaller than the sum of its proper divisors (386460).

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

331218 is a wasteful number, since it uses less digits than its factorization.

331218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18409 (or 18406 counting only the distinct ones).

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

The square root of 331218 is about 575.5154211661. The cubic root of 331218 is about 69.1891470612.

The spelling of 331218 in words is "three hundred thirty-one thousand, two hundred eighteen".