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Follow # Find Prime Factors of a number in javascript?

## We will discuss two methods to solve this problem using Javascript

Gaurav Patil
·Feb 22, 2023·

• Method 1: Division Method
• Method 2: Factor Tree Method
• Conclusion

Hi everyone today we Find Prime Factors of a number in javascript. let's discuss how to solve this problem statement. if you want to check out yesterday's problem click here.

Prime factorization is a way of expressing a number as a product of its prime factors. A prime number is a number that has exactly two factors, 1 and the number itself.

Example :

• Input: 15

• Output : 3 5

We will discuss two methods to solve this problem using Javascript

• Method 1: Division Method.

• Method 2: Factor Tree Method.

## Method 1: Division Method

### Algorithm

• step 1: Define a function named isPrime which takes an integer n as input.

• step 2. In the isPrime function, loop through all the integers from 2 to the square root of n.

• step 3. If any of the integers evenly divide n, return false because n is not a prime number.

• step 4. If none of the integers from 2 to the square root of n evenly divide n, return true because n is a prime number.

• step 5. Define a function named primeFactors which takes an integer n as input.

• step 6. In the primeFactors function, loop through all the integers from 2 to n.

• step 7. For each integer i, check if it is a prime number using the isPrime function.

• step 8. If i is a prime number, loop through n as long as it is divisible by i.

• step 9. For each iteration of the loop in step 8, divide n by i and print i to the console.

• step 10. After the loop in step 8 completes, move on to the next integer in the outer loop in step 6.

• step 11. When the outer loop in step 6 completes, the function has finished executing.

• step 12. Define a constant named n and set it equal to the value 90.

• step 13. Call the primeFactors function and pass in n as an argument.

• step 14. The prime factors of n will be printed on the console.

### Javascript Code

``````function isPrime(n) {
for (let i = 2; i <= Math.sqrt(n); i++) {
if (n % i === 0) {
return false;
}
}
return true;
}

function primeFactors(n) {
for (let i = 2; i <= n; i++) {
if (isPrime(i)) {
let x = n;
while (x % i === 0) {
console.log(i + " ");
x /= i;
}
}
}
}

const n = 90;
primeFactors(n);
``````

2 3 3 5

## Method 2: Factor Tree Method

### Algorithm

• step 1: Define a function named primeFactors which takes an integer n as input.

• step 2: While n is even, print 2 to the console and divide n by 2.

• step 3: Loop through odd integers from 3 up to the square root of n.

• step 4: If i is a factor of n, print i to the console and divide n by i.

• step 5: Repeat step 4 as long as i is a factor of n.

• step 6: If n is greater than 2, it is also a prime factor, so print it to the console.

• step 7: Define a constant named n and set it equal to the value 90.

• step 8: Call the primeFactors function and pass in n as an argument.

• step 9: The prime factors of n will be printed to the console.

### Javascript Code

``````function primeFactors(n) {
while (n % 2 === 0) {
console.log(2 + " ");
n /= 2;
}

for (let i = 3; i <= Math.sqrt(n); i += 2) {
while (n % i === 0) {
console.log(i + " ");
n /= i;
}
}

if (n > 2) {
console.log(n);
}
}

const n = 90;
primeFactors(n);
``````

2 3 3 5