untrue vs wrong number

untrue

adj
  • Not faithful or loyal. 

  • False; not true. 

wrong number

noun
  • A telephone number dialled by mistake, for example by transposing digits. 

  • A telephone call received from an unfamiliar caller, due to a mistake in the number dialled. 

How often have the words untrue and wrong number occurred in a corpus of books? (source: Google Ngram Viewer )