7 12 - 4 12 is exactly divisible by which of the following number?

xⁿ - yⁿ is divisible by x + y and x - y for all n.
7¹² - 4¹² is divisible by 7 + 4 and 7 - 4
⇒ 7¹² - 4¹² is divisible by 11 x 3 = 33