Zetta is a prefix used with the metric system that is equal to 1021, or 1,000,000,000,000,000,000,000 (sextillion). A good example of where this prefix is used with computers is with a ZB (zettabyte).
What prefix is before a zetta?
An exa is the prefix used before a zetta.
What prefix is after a zetta?
A yotta is the prefix used after a zetta.