The official real-illions.

Billion: 9 zeros
Trillion: 12 zeros
Quadrillion: 15 zeros
Quintillion: 18 zeros
Sextillion: 21 zeros
Septillion: 24 zeros
Octillion: 27 zeros
Nonillion: 30 zeros
Decillion: 33 zeros
Undecillion: 36 zeros
Duodecillion: 39 zeros
Tredecillion: 42 zeros
Quattuordecillion: 45 zeros
Quindecillion: 48 zeros
Sexdecillion: 51 zeros
Septendecillion: 54 zeros
Octodecillion: 57 zeros
Novemdecillion: 60 zeros
Vigintillion: 63 zeros
Centillion: 303 zeros


... and then across the pond...