Every Day Counts
All Prime Days
Date of birth
Enter your date of birth. Find out when you will be celebrating!

Here they are - all your prime days.

The largest known prime number is currently the Mersenne prime 257,885,161 - 1 which is a number comprising 17,425,170 digits.

Many of the largest known primes are Mersenne primes. If you have recently celebrated this Prime Day, please let us know as we'd be fascinated to know how you did it.