I extended my spreadsheet to numbers of less than 3 digits and there are lots of small solutions. As n gets smaller there are multiple values of N
I found it interesting to note that for each of n=3, 4, 5, 6, 7, 8 the largest value of N is the same: 146855520 This is because N has all the right factors N = 2^5 * 3^2 * 5 * 7 * 17 * 857