Sex*til"lion (?), n. [Formed (in imitation of million) fr. L. sextus sixth, sex six: cf. F. sextilion.] According to the method of numeration (which is followed also in the United States), the number expressed by a unit with twenty-one ciphers annexed. According to the English method, a million raised to the sixth power, or the number expressed by a unit with thirty-six ciphers annexed. See Numeration.

Sex*til"lion (?), n. [Formed (in imitation of million) fr. L. sextus sixth, sex six: cf. F. sextilion.] According to the method of numeration (which is followed also in the United States), the number expressed by a unit with twenty-one ciphers annexed. According to the English method, a million raised to the sixth power, or the number expressed by a unit with thirty-six ciphers annexed. See Numeration.

• Western (Arabic) Numeral: Sextillion, 1021
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• Usually means a trillion billion, That is to say, a 1 followed by 21 zeros, 1021
  
• (Dated usage, notably British) A million quintllion or a 1 followed by 36 zeros, 1036