JavaScript Program to Check Perfect Number

Posted in JavaScript Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 359 - Views

⏳ 4 mins

💬 1 Comment

JavaScript Program to Check Perfect Number

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, exploring the properties of numbers is a fascinating task. One such special type of number is a perfect number.

A perfect number is a positive integer that is equal to the sum of its proper divisors (excluding itself).

In this tutorial, we will explore a JavaScript program designed to check whether a given number is a perfect number.

The program involves finding the divisors of the number and checking if the sum of these divisors equals the original number.

📄 Example

Let's delve into the JavaScript code that accomplishes this task.

isPerfectNumber.js

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// Function to check if a number is a perfect number
function isPerfectNumber(number) {
  let sum = 0;

  // Find divisors and calculate the sum
  for (let i = 1; i <= number / 2; i++) {
    if (number % i === 0) {
      sum += i;
    }
  }

  // Check if the sum of divisors is equal to the original number
  return sum === number;
}

// Driver program
// Replace this value with the number you want to check
const number = 28;

// Call the function to check if the number is a perfect number
if (isPerfectNumber(number)) {
  console.log(`${number} is a perfect number.`);
} else {
  console.log(`${number} is not a perfect number.`);
}

💻 Testing the Program

To test the program with different numbers, modify the value of number in the code.

Output

28 is a perfect number.

Run the script to check if the specified number is a perfect number.

🧠 How the Program Works

The program defines a function isPerfectNumber that takes a positive integer number as input and returns true if the number is a perfect number, and false otherwise.
Inside the function, a loop is used to find divisors of the number and calculate their sum.
The program checks if the sum of divisors is equal to the original number.
Inside the main program, replace the value of number with the desired number you want to check.
The program calls the isPerfectNumber function and prints the result using console.log.

📏 Between the Given Range

Let's delve into the javascript code that identifies perfect numbers in the specified range.

findPerfectNumbersInRange.js

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// Function to check if a number is perfect
function isPerfectNumber(number) {
  let sum = 0;
  for (let i = 1; i < number; i++) {
    if (number % i === 0) {
      sum += i;
    }
  }
  return sum === number;
}

// Function to find and display perfect numbers in the range
function findPerfectNumbersInRange(start, end) {
  let perfectNumbers = [];
  for (let num = start; num <= end; num++) {
    if (isPerfectNumber(num)) {
      perfectNumbers.push(num);
    }
  }
  return perfectNumbers;
}

// Driver program
// Set the range from 1 to 50
const startRange = 1;
const endRange = 50;

// Call the function to find perfect numbers
const perfectNumbersInRange = findPerfectNumbersInRange(startRange, endRange);

// Display the perfect numbers
console.log(`Perfect Numbers in the Range ${startRange} to ${endRange}:`);
console.log(perfectNumbersInRange.join(' '));

💻 Testing the Program

Output

Perfect Numbers in the range 1 to 50:
6 28

Run the script to see the perfect numbers in the specified range.

🧠 How the Program Works

The program defines a function isPerfectNumber to check if a given number is a perfect number.
It also defines a function findPerfectNumbersInRange to find perfect numbers in a specified range.
The main section sets the range from 1 to 50 and calls the function to find and display perfect numbers in that range.

🧐 Understanding the Concept of Perfect Number

Before delving into the code, let's understand the concept of perfect numbers. A perfect number is a positive integer that is equal to the sum of its proper divisors (excluding itself).