If we are not sorting dates, spelling the month or an abbreviation is better because it avoids confusion. The third thing to do, especially where sorting is concerned, is to use year, month, day order. This is the logical way of presenting it. Say 2001 November 7, not November 7, 2001. 2001 November 7 1900.
Military dates are also Ok, but they are in reverse order.
7 Nov 2001 can be sorted, but it has to be done backwards.