NLTagger not getting number 46

I'm working with NLTagger to enumerate tags to know what kind of word is in a sentence. If I have "Route 45" I get "Noun" for Route and "Number" for 45. It is working ok except for number 46.

If I have "Route 46" I get "Noun" for Route and "Pronoun" but if I only have a String with "46" it gets identified as a Number.

Does anyone know what is happening here?

NLTagger not getting number 46
 
 
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