TKD says:

"Numbers are used as nouns. As such, they may stand alone as subjects or objects or they may modify another noun."

I would understand that to mean I can put noun suffixes on them like I can with nouns and other words that are used as nouns. 

rav wejDIchDaq puch pa' tu'lu' - There is a restroom on the third floor
juHwIj 'oH qech wa'maH cha'DIch'e' - The 22nd building is my home
tlhInganHey ghaH nov wejDIchqoq'e' - The so-called "third" alien is apparently a Klingon

qurgh