Q: prime factor 69420
A: not going to do it, except it seems easy, 6942, by 3 is 2314, in half is 1157, no 3, check 7, no, 11 from left, no, 19 (or57) from right, no, 13 on right is 117 YES, that means 13x9 minus 1 in next place, is 89. so 89x13, times 2, x3, x10, which means: 2x2x3x5x13x89