16069...54321 (113-digits)

This number is a prime.

                             160 6958575655 5453525150 5948474645 4443424140
4938373635 3433323130 3928272625 2423222120 2918171615 1413121110 1987654321

The first prime formed by concatenating the reversals of natural numbers from n to 1. Here, n = 61. [Marcel]