A yobibyte is a unit of storage equal to 280 bytes.

its allot off memory don't get it its expensive

No, because there is no such thing as a yobibyte memory card, and even if it did exist it would exceed the addressing limits of the hardware of your cellphone.

Currently, inside a regular desktop PC the largest unit of size would be 1 TB (1000 GB), and with this unit it becomes very difficult to completely fill the storage device.

However, potentially, the largest is the yobibyte, which is a whopping 10,000,000,000,000,000,000 bits of data. Basically, if scaled down into human language it would be the information capacity of the observational universe, meaning every bit of known knowledge ever recorded, translated into every language and coppied 10,000,000 times over.