Informally, zillion means a very large, indefinite quantity. It is often used for humor and exaggeration, with variants such as gazillion or bazillion.

Andrew Schilling (the four-year-old creator of zootzootplex) invented sillion ("like zillion, but sillier") and sillyillion ("like sillion, but bigger").[1] San Francisco eccentric and protester Frank Chu often writes zillion-like numbers on his signs, such as deskrothullion, cletrostallion, or resgroshillion.[2]


Conway and Guy defined n-zillion to mean \(10^{3n+3}\).[3] In cooperation with Allan Wechsler, the system was extended to xilliyillizillion \(= (10^6x+10^3y+z)\)-zillion, using "n" for x, y, or z lest any of them be zero. For example, a quadrillitrillinillion is \(10^{3\left(10^6\cdot 4+10^3\cdot 3+0\right)+3} = 10^{3\cdot 4,003,000 + 3}\) in the American system. In the system formerly used in the UK, n-zillion would instead be \(10^{6n}\).


  1. A few hefty numbers
  2. Fitzpatrick, Chris. Or Maybe It's Something Completely Different: Frank Chu and the 12 GalaxiesNero Magazine
  3. The Book of Numbers by J. H. Conway and R. K. Guy

See also

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