million vs quintillion

million

num

  • The cardinal number 1,000,000: 10⁶; a thousand thousand. 

  • An unspecified very large number. 

quintillion

num

  • A billion billion: 1 followed by eighteen zeros, 10¹⁸. 

noun

  • Any very large number, exceeding normal description. 

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