For introduction, Ethiointegers are integers which get reversed when multiplied by another number. For instance, 2178 * 4 = 8712 1089 * 9 = 9801 I couldn't find such numbers, even by another name anywhere else except in one journal which I think is not electronically accessible. **My question**: Has numbers like this been treated anywhere? If so, what interesting properties do they have? [E.g. One property I consider interesting: sumofdivisors(1089) = 1729 = 1728 + 1 (Hardy's taxi number 12^3 + 1^3, [ more about this sum][1] ), also 1728 is a rearrangement of 2178!] [Added later] Eulertotient(2178) = Eulertotient(1089) [1]: http://www.mathpages.com/home/kmath028.htm