Hierarchy

Tier 1 (Basic)
Million

Billion

Trillion

Tier 2 (Less Known)
quadrillion

Quintillion

Sextillion

Septillion

octillion

Nonillion

Decillion

Tier 3 (Higher Decillions)
Undecillion

Duodecillion

Tredecillion

Quattuordecillion

Quindecillion

Sexdecillion

Septendecillion

Octodecillion

Novemdecillion

Vigintillion

Tier 4 (Higher Vigintillions)
Unvigintillion

Duovigintillion

Trevigintillion

Quattuorvigintillion

Quinvigintillion

Sexvigintillion