I think it would be N=10 since:
N! = 6*7*24*60*60 = 1*2*3*7*(4*6)*(5*3*2*2)*60 = 1*2*3*4*5*6*7*(3*2*2*5*3*2*2) = 7!*(2*2*2)*(3*3)*(2*5) = 7!*8*9*10 = 10!
If a + b + c = 8 a.b.c = 27 then Is there exist solution/s in (a,b,c) where a, b and c are positive real numbers?