There's 1 bit.
8 bits make one Byte.
1024 Bytes make one Kilobyte.
1024 Kilobytes make one Megabyte.
1024 Megabytes make one Gigabyte.
1024 Megabytes make one Terabyte.
1024 Terabytes make one Petabyte.
1024 Petabytes make one Exabyte.
1024 Exabytes make one Zettabyte.
1024 Zettabytes make one Yottabyte.
One Yottabyte is 1,208,925,819,614,629,174,706,176 bytes.
*Exa, Zetta, and Yotta are legitimate names, and not pulled out of Flanker's [backside].*