ŋō is one of my favorite numbers. As a number it means 140 in base 8 (96 base 10), but really it simply means “lots”, which is why it is so short. The other way to say 140, the way to say it when counting is: ōru aþāllōr, as in ōru awījtōr aþōnne (137), ōru aþāllōr (140), ōru aþāllōr aþān (141).
So how did a little word like ŋō come to mean 140 (96)? Poetry. There is this famous poem about the journey from the Kēlen homeword to Tērjemar involving ŋō ōraen (many thousand) groups of people and their leaders, and then the poem goes on to name names, and there are 96 names listed. This implied to subsequent generations that there were 96 thousand groups.