Python Program to Compute Prime Factors of an Integer

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In this post, we’ll look at a Python program that prints out all the prime factors of a given number. A number is considered to be a prime factor of another number if it is a prime number and perfectly divides the given number. In this section, we will look at what a prime factor is, how to discover a prime factor, and the python program.

A number’s prime factors are the prime numbers that, when multiplied together, give the number. Two conditions can be used to determine a number’s prime factor:

The digit should be a prime number.

The number should perfectly divide the number.

Examples:

Example1:

Input:

given number =240

Output:

The prime factors of the given number are : 
2
3
5

Example2:

Input:

given number =33

Output:

Enter some random number = 33
The prime factors of the given number are : 
3
11

Program to Compute Prime Factors of an Integer in Python

There are several ways to compute prime factors of an integer in python some of them are:

Using while loop (Static Input)
Using while loop (User Input)
Efficient Method (User input)

Method #1: Using while loop (Static Input)

Approach:

Give the integer value as static input.
Using a while loop, first determine the number’s components.
Calculate whether the factors are prime or not using another while loop within the previous one.
Exit of program.

Below is the implementation:

# given number
numb = 240
# Printing the prime factors
print("The prime factors of the given number are : ")
value = 1
while(value <= numb):
    k = 0
    if(numb % value == 0):
        j = 1
        while(j <= value):
            if(value % j == 0):
                k = k+1
            j = j+1
        if(k == 2):
          # printing the prime factor
            print(value)
    # incremeent the value by 1
    value = value+1

Output:

The prime factors of the given number are : 
2
3
5

Explanation:

Given the number as static input.
The while loop is utilized, and the integer factors are obtained by using the modulus operator and determining whether the remainder of the number divided by value is zero.
The integer’s factors are then checked again to see if they are prime.
The factor of an integer is prime if it has two factors.
The integer’s prime factor is printed.

Method #2: Using while loop (User Input)

Approach:

Scan the number using int(input()) function.
Using a while loop, first determine the number’s components.
Calculate whether the factors are prime or not using another while loop within the previous one.
Exit of program.

Below is the implementation:

# Scan the number using int(input()) function.
numb = int(input("Enter some random number = "))
# Printing the prime factors
print("The prime factors of the given number are : ")
value = 1
while(value <= numb):
    k = 0
    if(numb % value == 0):
        j = 1
        while(j <= value):
            if(value % j == 0):
                k = k+1
            j = j+1
        if(k == 2):
          # printing the prime factor
            print(value)
    # incremeent the value by 1
    value = value+1

Output:

Enter some random number = 220
The prime factors of the given number are : 
2
5
11

Method #3:Efficient Method (User input)

Approach:

Scan the given number using int(input()) function.
We will print 2 and divide numb by 2 while it is divisible by 2.
Following step 2, numb must always be odd.
Begin a loop with I = 3 and work your way up to the square root of n. If I divide numb by I print I and divide numb by i. If we unable to divide numb , increase the I value by 2 and proceed.
If numb is a prime number and higher than 2, it cannot be reduced to 1.
So, if numb is larger than 2, print it.

Below is the implementation:

import math
# Scan the number using int(input()) function.
numb = int(input("Enter some random number = "))
# Printing the prime factors
print("The prime factors of the given number are : ")
while numb % 2 == 0:
      print(2),
      numb = numb / 2

   # n became odd
for i in range(3,int(math.sqrt(numb))+1,2):
    while (numb % i == 0):
        print (int(i))
        numb = numb / i
    
if numb > 2:
    print (int(numb))

Output:

Enter some random number = 33
The prime factors of the given number are : 
3
11

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