rightmost non zero digit cam found out by the formula: let the Number be N==> N! => find the remainder of below expression divided by 10 or just find its unit didgit: [N/5]! * 2^(N/5) *[ [N/5](remainder)]
repeat the steps..and you can find the ans: [113/5)! * 2^9113/5) * (remainder of 113/5)! 22! * 2^22 * 3! repeat for 22! and continue.