19697...79691 (65-digits)

This number is a composite.

     19697 9693969796 9696979693 9697969096 9796939697 9696969796 9396979691

Delete each digit if the position is even (167636766676367606763676667636761), repeat until only 2 digits (17376737073767371 -> 136303631 -> 16061 -> 101 -> 11), and all are palindromic primes. [Marcel]