While writing a treasure hunt inspired by the DEFCON badge challenges, I needed a prime phone number. That is, a phone number which also happens to be a prime number.
Using the Twilio API, I made a script to find prime phone numbers. Prime numbers are the coolest numbers out there (apart from e and π). So I built primenumbers.io where you can find your very own prime phone number.
You can view a tutorial about how this site works here.