Counting to 1000
- Thread starter Cannon
- Start date
67 is:
- the 19th prime number (the next is 71)
- a Chen prime
- an irregular prime
- a lucky prime
- a Heegner number
- a Pillai prime since 18! + 1 is divisible by 67, but 67 is not one more than a multiple of 18.
- a super-prime (19 is prime)
- an isolated prime (65 and 69 are not prime)
