\begin{definition}[Definition:Kaprekar's Constant]
Let $n \in \Z_{>0}$ be a positive integer with $4$ digits, not all of which are equal.
Let Kaprekar's process be applied to $n$.
The number reached after no more than $8$ iterations is known as '''Kaprekar's constant''', and has the value of $6174$.
{{NamedforDef|Dattathreya Ramchandra Kaprekar|cat = Kaprekar}}
\end{definition}