yottabyte

The yottabyte is a multiple of the unit byte for digital information. 

A yottabyte is 1024 or 1,000,000,000,000,000,000,000,000 bytes. Abbreviation for yottabyte is YB. One yottbyte is equal to 1.000 zettabytes and is the largest SI unit of measurement. It is used for measuring data.