The increase (or rate of growth) of a factorial is faster than all polynomials and exponentials.
The graphs of n vs n! and n vs ln(n!), where 'ln' represents natural logarithm, are shown adjacent.
Since the symbol, Π is used to represent product of numbers, the factorial function can be represented as

n!	=
	=	1 . 2 . 3 . . . . (n – 2) . (n – 1) . n
	=	n . (n – 1) . (n – 2) . . . . 3 . 2 . 1
Since (n – 1)! = (n – 1) . (n – 2) . . . . 3 . 2 . 1 we have
n!	=	n . (n – 1)!
	=	n . (n – 1) . (n – 2)!
	=	n . (n – 1) . (n – 2) . (n – 3)! etc.

Example: