Reverse of a number

The reverse of a number is a mathematical method to obtain from a number another written in the opposite way to the first.

For example, the reverse of 1234 is 4321. 

 Method 
Given a positive integer , the integer which has the same digits in the reverse order is:

 Applications 
Obtaining the reverse of a number is useful to predict if a number is Lychrel or not.

 References 

Category:Number theory