freeCodeCamp/guide/english/certifications/coding-interview-prep/project-euler/problem-3-largest-prime-factor/index.md

title
Largest prime factor

Problem 3: Largest prime factor

Method:

• To find the largest prime factor of a number, we start from the smallest prime factor 2 and divide the number with it.
• If the remainder is 0 that means the number is divisible by that prime number, we keep dividing the number by same prime number until that number is no more divisible by that prime number.
• After that, we incrememnt the prime factor by 1 and repeat this process till the number becomes 1.

Solution:

function largestPrimeFactor(number) {
  let prime = 2, max = 1;
  while (prime <= number){
    if (number % prime == 0) {
      max = prime;
      number = number/prime;
    }
    else prime++; //Only increment the prime number if the number isn't divisible by it
  }
  return max;
}

• Run Code

Resources:

• Wikipedia