# Python program to reverse a given number (2 different ways)

Reversing a number in Python: Here, we are going to learn different ways to reverse a given number in Python.
Submitted by Ankit Rai, on July 28, 2019

Take input number from the user and print its reverse.

Example:

```    Input:
12345

Output:
54321
```

Here, we are implementing program to reversing a given number using 2 different ways.

1) Famous approach for reversing the number: Take input from the user and typecast into an integer, then iterate in the loop till num is not become zero, inside the loop:

• Find out the remainder.
• Using this: rev_num = rev_num * 10 + remainder.
• Update that number by diving by 10.
• After coming out of the loop printing the reverse number.
```if __name__ == "__main__" :

# take string input from user
num = int(input('Enter a number: '))

rev_num = 0

# iterate the loop till num is not equal to zero
while(num) :
rem = num % 10
rev_num = rev_num* 10 + rem
num //= 10

print('Reverse number is: ', rev_num)
```

Output

```Enter a number: 12345
Reverse number is:  54321
```

2) Make a user-defined function for reversing the Number: Take input from the user and typecast into integer, thenreverseNum() function call.

Inside the function:

• Iterate in the loop till num does not become zero:
• Find out the remainder.
• Using this: rev_num = rev_num * 10 + remainder.
• Update that number by diving by 10.
• After coming out of the loop returning the reverse number to the main.
```# define a function for finding
# reverse of the number
def reverseNum(num) :

rev_num = 0

# iterate the loop till num is not equal to zero
while(num) :
rem = num % 10
rev_num = rev_num* 10 + rem
num //= 10

return rev_num

# Main() method
if __name__ == "__main__" :

# take string input from user
num = int(input('Enter a number: '))

print('Reverse number is: ', reverseNum(num))
```

Output

```Enter a number: 12345
Reverse number is:  54321
```

Preparation