Reverse Prime Composite Numbers
The story begins with an observation made to me by my father, on 22 February 2022, that it is a special date. Afterwards, I found out he was representing this date as 20220222 (year first, month and then day). In my original interpretation, it was 22022022. I was not satisfied just with the fact that this is a palindrome (a number which, when reversed, gives back the same number). So I looked into its prime factors: 22022022 = 2 x 3 x 11 x 2 x 3 x 11 x 333667. After a while of staring at this, I checked what would happen if I reversed 333667. That number (766333) turned out to be a prime as well! I learned afterwards that prime numbers whose reverse (in decimal notation) are prime, are called reverse primes. So then 22022022 is a composite reverse prime, i.e., a natural number who all prime factors are reverse primes. The question was: how special does this make the number 22022022? To be continued.