Is That Prime? Is the most powerful and intuitive prime number, composite number and factor calculator on the app store. It’s also the fastest taking mere seconds for calculations of even the largest of numbers. Is That Prime? Tells you whether a number is prime or composite, and can then tell you the number’s factors, listing them in a grouped format or an ascending format. It can handle calculations of numbers up to 9999999999999.
Is That Prime? by Nicholas Cooke on the App Store (iPhone, iPad, iPod touch, iPad Mini, iOS, iPad Air)