its a pretty simple method:

if the number to factorize ends in 9 i know one of its factors its gonna end on 1 3 7 or nine

a 4 or a 2 is not posible

so i iterate through all posible two digits number attached to 1 3 7 or 9 multiplied by another number from zero to nine and select only those whos product termination match the original number and go on like that till the begining of the number

BRN441