Python: Reverse the digits of a given number and add it to the original

Last update on April 17 2025 13:05:54 (UTC/GMT +8 hours)

Palindrome Sum Iteration

Write a Python program to reverse the digits of a given number and add them to the original. Repeat this procedure if the sum is not a palindrome.

Note: A palindrome is a word, number, or other sequence of characters which reads the same backward as forward, such as madam or racecar.

Visual Presentation:

Python: Reverse the digits of a given number and add it to the original

Sample Solution:

Python Code:

# Function to reverse a number and add it to the original number until a palindrome is obtained
def rev_number(n):
    s = 0  # Initialize a variable to count the number of iterations
    while True:
        k = str(n)  # Convert the number to a string for comparison
        if k == k[::-1]:  # Check if the number is a palindrome
            break  # If it is a palindrome, exit the loop
        else:
            m = int(k[::-1])  # Reverse the digits and convert back to an integer
            n += m  # Add the reversed number to the original number
            s += 1  # Increment the iteration count
    return n  # Return the palindrome obtained

# Test cases
print(rev_number(1234))  # Example: 1234 + 4321 = 5555 (palindrome)
print(rev_number(1473))  # Example: 1473 + 3741 = 5214 + 4125 = 9339 (palindrome)

Sample Output:

5555
9339

Explanation:

Here is the breakdown of the above Python exercise:

Function Definition: The function "rev_number()" takes an integer 'n' as input.
Initialization: Initializes a variable 's' to count the number of iterations.
Palindrome Check and Transformation:

Enters a loop that continues until the number 'n' becomes a palindrome.
Converts the current number 'n' to a string 'k'.
Checks if 'k' is equal to its reverse (k[::-1]), indicating a palindrome.
If not a palindrome, reverse the digits of n (m) and adds it to 'n'.
Increments in the iteration count 's'.

Return Palindrome: Returns the final palindrome obtained.
Test Cases:

Calls the rev_number function with different initial numbers to demonstrate the transformation into palindromes.
Example: rev_number(1234) results in 5555 because 1234 + 4321 = 5555, which is a palindrome.
Example: rev_number(1473) results in 9339 after multiple iterations, forming a palindrome.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to multiply a number by its reverse repeatedly until the product is a palindrome.
Write a Python program to subtract the reverse of a number from the number repeatedly until a palindrome is reached.
Write a Python program to convert a number to a string and check for palindrome status, iterating an operation until it becomes palindromic.
Write a Python program to determine the number of iterations required for a given number to become a palindrome when adding its reverse.

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Previous: Write a Python program to print the length of the series and the series from the given 3rd term , 3rd last term and the sum of a series.
Next: Write a Python program to count the number of carry operations for each of a set of addition problems.

Python Code Editor:

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