Find the largest prime divisor of 11! + 12! + 13!.
Nice work, or you could simplify.
11!(1 + 12 + 12*13)
11!(169)
11! * 13 * 13
=^._.^=
Find the largest prime divisor of 11! + 12! + 13! ==6,745,939,200 = 2^8 * 3^4 * 5^2 * 7 * 11 * 13^2
13 is the largest prime divisor.