What are all the digits of the factorial of 69 and how many digits ? What is the gogol number ? How many integers of the form 10^n+1 are prime ? (like 101) Want to know if a big integer is prime ? The change mod function indicates when the number is prime. Want to know the divisors of an integer ? A prime divisor has no inverse modulo this integer. This is a modulo calculator overpowering almost limitless! (only display is limited !) With modulo gogol, calculus are exact until 100 digits ! The "n!" button calculates the factorial of an integer from 0 to 500. Factorial are limited to factorial of 500, but the calculator could calculate them to over 1000 ! (soon on iPad) The "change mod" (change modulo) function indicates when the modulo is prime. There are no limit to the modulo except the display. The "mod gogol" button set a modulo to 10^100 (gogol number). You can stoke one number and recall it when you want. The "Mod" operation indicates the residue modulo N. The exp function allow modular exponentiation (as + - *) The "INV" function calculates the inverse of an integer modulo N. This app is intended for both mathematics teachers and/or their students, or if you are interested in the beauty of numbers. Enjoy calcMod-ProX ! Les commentaires sont disponibles en français (réglages).