It's a straightforward question today. Calculators are allowed for this question because we here do not feel that six-digit multiplication is worth the effort. I mean, we know you COULD do it, but that's what a tool is for, right?
factorial notation, n!, meaning multiply the integer n by all the positive integers less than n. (Yeah, n must be a positive integer to begin with.)
For example, 6! = 6*5*4*3*2*1 = 720
For completeness, 0! = 1
Thanks to Darren, Right on the Left Coast, for this one.