The GCD of given numbers is 13.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}2613 =& 3\cdot13\cdot67\\[8pt]2171 =& 13\cdot167\\[8pt]\end{aligned}$$(view steps on how to factor 2613 and 2171. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}2613 =& 3\cdot\color{blue}{\boxed{13}}\cdot67\\[8pt]2171 =& \color{blue}{\boxed{13}}\cdot167\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 13 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.