The factorial of a number n is defined by the product of all the digits from 1 to n (including 1 and n). For example, 4! = 4*3*2*1 = 24 6! = 6*5*4*3*2*1 = 720 Note: It is denoted by n! and is calculated only for positive integers. Factorial of 0 is always 1. The simplest way to find the factorial of a … Continue reading Factorial Using PHP