Finding perfect numbers in JavaScript

A perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. A divisor of an integer x is an integer that can divide x evenly.

For example −

28 is a perfect number, because
28 = 1 + 2 + 4 + 7 + 14

We are required to write a JavaScript function that takes in a number, say n, and determines whether or not n is a perfect number.

Example

const num = 28;
const checkPerfectNumber = (num = 1) => {
   if(num === 1) {
      return false;
   };
   let sum = 1;
   for(let i = 2; i <= Math.floor(Math.sqrt(num)); i++){
      if(num % i === 0) {
         sum = sum + i + num / i; if(sum > num) {
            return false;
         }
      };
   };
   return sum === num;
};
console.log(checkPerfectNumber(num));

Output

And the output in the console will be −

true

AmitDiwan

Published on 21-Nov-2020 10:31:53