Donna, A woman can have her own SS# with an A, or it can be under her husband's # with a B. If the husband passes away, the B can be changed to a D. Even when a woman remarries after her first husband passes away, it may be possible that she keeps the # that she had while her first husband was alive. I think it depends on which # she receives her benefits under. If a person has more than one disabled child/dependent, each one will be given a # under the Father's SS#, but they will have a C1, C2, C3, etc. depending on how many children there are. Then, when that dependent gets older he/she can have their SS# changed to their own SS# with an A. There are many more possibilities. It someone worked for the Railroad, the alpha letter/letters will be in front of the SS#. They have their own list of meanings. Margaret