The GCD of given numbers is 691.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}507885 =& 3\cdot5\cdot7\cdot7\cdot691\\[8pt]60808 =& 2\cdot2\cdot2\cdot11\cdot691\\[8pt]\end{aligned}$$(view steps on how to factor 507885 and 60808. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}507885 =& 3\cdot5\cdot7\cdot7\cdot\color{blue}{\boxed{691}}\\[8pt]60808 =& 2\cdot2\cdot2\cdot11\cdot\color{blue}{\boxed{691}}\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 691 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.