It all depends on how your data is standardized, but if the numbers are always in the last positions as in your example:
AV NOSSA SENHORA DE COPACABANA 664
AV DOM SEVERINO
AV DOM HELDER CAMARA, 5332
R PROJETADA 05 S/N
ROD BA-526 305
You could use a set of functions to achieve what you want, something like this:
=SE(ÉERRO(VALOR(DIREITA(A1;CORRESP(" "; ÍNDICE(EXT.TEXTO(A1;NÚM.CARACT(A1)-LIN(INDIRETO("1:"&NÚM.CARACT(A1)))+1;1);0);0)-1)));"S/N";VALOR(DIREITA(A1;CORRESP(" "; ÍNDICE(EXT.TEXTO(A1;NÚM.CARACT(A1)-LIN(INDIRETO("1:"&NÚM.CARACT(A1)))+1;1);0);0)-1)))
This is the complete formula, see below how I came up with this formula.
It's a bit long the set of formulas ... but it's simple, I'll try to separate and explain to understand better:
It checks the first space of the right for the left , because the data that gave the last characters are their numbers, and some have "S / N" others are no number, then it would be:
=CORRESP(" "; ÍNDICE(EXT.TEXTO(A1;NÚM.CARACT(A1)-LIN(INDIRETO("1:"&NÚM.CARACT(A1)))+1;1);0);0)
This is the hardest formula to really understand.
Search the data from right to left after the last whitespace:
=DIREITA(A1;[FÓRMULA DO ITEM 1 AQUI]-1)
Replace what is between [] (brackets) with the formula in item 1.
Verify that this result (item 2) is a number and returns that number or returns a text ("S / N" in case):
=SE(ÉERRO(VALOR([FÓRMULA DO ITEM 2 E 1]));"S/N";VALOR([FÓRMULA DO ITEM 2 E 1]))
Replace what is between [] (brackets) by the formula from item 2 and item 1 to have the complete formula.
I hope I have helped!