97 is the last prime with 2 digits....1/2....single digit numbers and primes......double digit numbers and primes.......1, 3, 7, and 9............are the only 4 possible end digits to a prime greater than 10.........10....like the base number system..........2 - 11.....one of the 2 prime fund......according to my homeless self anyways...2 is the other...2 - 11 is 10 numbers......like the base...97....is like 7 and 9.....half of the 4 possible end digits to any prime greater than 10....

97 and 89 and 67 and 71........the only 2 prime pairs amongst the 1st 25, 4 primes in all.....all under 100....to match one prime's single with the next prime's double digit.....

Like this......67, 71...........89, 97.......9 + 9 = 18.....97 + 89 = 186.........in E = mc^2.....c is the speed of light........186, 000 miles per second...