Problem 168Published on Friday, 16th November 2007, 05:00 pm; Solved by 1662; Difficulty rating: 65%
Consider the number 142857. We can right-rotate this number by moving the last digit (7) to the front of it, giving us 714285.
It can be verified that 714285=5×142857.
This demonstrates an unusual property of 142857: it is a divisor of its right-rotation.
Find the last 5 digits of the sum of all integers n, 10 < n < 10100, that have this property.