# Python : Find Factorial of Number Using Recursion

Tutorial by:Rizwan Abdullah      Date: 2016-06-16 01:52:11

The factorial of a number is the product of all the integers from 1 to that number. For example, the factorial of 6 (denoted as 6!) is 1*2*3*4*5*6 = 720. Factorial is not defined for negative numbers and the factorial of zero is one, 0! = 1.

## Source Code

``````
# Python program to find the factorial of a number using recursion

def recur_factorial(n):
"""Function to return the factorial
of a number using recursion"""
if n == 1:
return n
else:
return n*recur_factorial(n-1)

# take input from the user
num = int(input("Enter a number: "))

# check is the number is negative
if num < 0:
print("Sorry, factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
print("The factorial of",num,"is",recur_factorial(num))``````

Output 1

```
Enter a number: -2
Sorry, factorial does not exist for negative numbers
```

Output 2

```
Enter a number: 7
The factorial of 7 is 5040
```

Here, we ask the user for a number and use recursive function `recur_factorial()` to compute the product up to that number.

## Python

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