Just a little fait divers.
Repeat the string 1808010808 1560 times, and tack on a 1 the end.
The resulting 15601-digit number is prime, and because it’s a palindrome made up of the digits 1, 8, and 0, it remains prime when read backward, upside down, or in a mirror.
Very interesting!
I also wonder how people come up with these fun little tidbits