A exbibyte is a unit of data storage that equals 2 to the 60th power, or 1,152,921,504,606,846,976 bytes.
While a exabyte can be estimated as 10^18 or 1,000,000,000,000,000,000 bytes, a exbibyte is exactly 1,152,921,504,606,846,976 bytes. This is to avoid the ambiguity associated with the size of exabytes. A exbibyte is 1,024 pebibytes and precedes the zebibyte unit of measurement.
For a list of other units of measurements, view this Help Center article.