12233...88889 (36-digits)

This number is a prime.

                                     122333 4444555556 6666677777 7788888889

Just showing those entries submitted by 'Oudra': (Click here to show all)

An easy-to-remember prime; Write one 1, two 2's, three 3's, ... , eight 8's, then replace the last digit with a 9. [Oudra]