How do you find the prime factor of a number in python while loop?

In this post, you will learn a Python program to print prime factors of a number. Before starting the coding part, it should be clear about the prime number and prime factor.

A prime number is a whole number greater than 1, whose only factors are 1 and itself. The prime numbers, which divide the given number perfectly, are known as the prime factors of that number. Basically, it is finding prime numbers that prime numbers multiply together to make the original number. The prime factorization serves useful when working with big numbers, such as in Cryptography or it is a commonly used in mathematical problem to secure public-key encryption systems. For example, if the input number is 110, then the output should be "2 5 11". And if the input number is 99, then the output should be "3 11". With the help of these two conditions, we can check whether a number is a prime factor of a given number or not-

• The number must be a prime number.
• The number must perfectly divide the given number.

Program to find prime factors using for loop

Here is the program to find the prime factors of a number using Python. This program allows the user to enter any positive integer using the input[] method. Next, Python returns the prime factors of that number using the nested for loop.

# Python Program to find Prime Factors of a Number
 
num = int[input[" Please enter any number: "]]

for x in range[2, num + 1]:
    if[num % x == 0]:
        chk_prime = 1
        for y in range[2, [x //2 + 1]]:
            if[x % y == 0]:
                chk_prime = 0
                break
            
        if [chk_prime == 1]:
            print[" %d is a Prime Factor of the given number %d" %[x, num]]

Output of the above code -

In the above example, we have used the for loop only. Firstly, we have taken the input from the user using the input[] method and stored it in a variable num. Then, we have applied the for loop from x=2 to x=num+1. Next, we check if the modulo of the value of x and number is equal to 0. Then we keep the count value = 1 and again apply the for loop inside the for loop from y=2 to y=x//2+1. and check the given if condition. If the condition is satisfied, the count value is set to 0 and we break the statement. Then we come out of the for loop and check the condition if count ==1 and print the value of x. Hence the prime factors are printed with their single-single value.

Program to find prime factors using While loop

Here, we take a number from user input and store it in a variable. Next, we obtain the factors of a number with the help of a nested while loop and find whether the factors are prime or not.

# Python Program to find Prime Factors of a Number
 
num = int[input[" Please enter any number: "]]

x = 1

while[x  2:
      print [n]

n = int[input["Enter the number for calculating the prime factors :\n"]]
primefactors[n]

Output:

Enter the number for calculating the prime factors :
650
2
5
5
13

#using for loop

n = int[input["Enter the number for calculating the prime factors :\n"]]
for i in range[2,n + 1]:
    if n % i == 0:
        count = 1
        for j in range[2,[i//2 + 1]]:
            if[i % j == 0]:
                count = 0
                break
        if[count == 1]:
            print[i]

Enter the number for calculating the prime factors :
350
2
5
7

NOTE:

Suppose we take input as 650 : the prime factors are 2,5,5,13
so, it will print 2,5,13 as all integers one time.

#using while loop

n = int[input["Enter any Number for calculating the prime factors: "]]
i = 1

while[i