[ September 12, 1999 ] Palindrome 93639 is as far as I know a very unique one.
All we need to perform is adding to it the sum of its prime factors.
This gives the ending prime 93683.
( Note : sometimes more iterations are needed to reach an ending prime.)
93639 + 3 + 7 + 7 + 7 + 7 + 13 = 93683
The uniqueness exists therein that there is NO OTHER PRIME between 93639 and 93683 !
It is easily stated of course, so can you find a second palindrome with this property ?
[ Visit and participate also Carlos Rivera's Puzzle #66.]