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# Program to find largest prime factor of a number

by | Dec 26, 2020 | Python Programs

Home » Python » Python Programs » Program to find largest prime factor of a number

## Introduction

The task is to find largest prime factor of a given positive integer. ## Program

```import math
def find(ip_int):
large_prime = -1
ip_int = int(ip_int)
# Find total number of 2’s dividing the number
while ip_int % 2 == 0:
large_prime = 2
ip_int /= 2
# Find all prime numbers
for num in range(3, int(math.sqrt(ip_int)) + 1, 2):
while ip_int % num == 0:
large_prime= num
ip_int = ip_int / num
if ip_int > 2:
large_prime = ip_int
return int(large_prime)
ip_int = input("Enter the positive integer: ")
print("The largest prime factor is: ", find(ip_int))
```

## Output: ## Explanation

In the code, we have found all the prime factors of the number 42 i.e. 2 * 3 * 7 and returned the largest number.

## Author

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