It is one thousand million volts

(1,000,000,000) One billion volts.

In terms of power, "giga" represents a unit equivalent to one billion, typically used in the context of computing and data storage capacities. For example, 1 gigawatt is equal to one billion watts of power.

0.00244140625 gigabytes == Bytes are storage units defined for data to be kept(/transfered) in(/to-from) computer. 1 Byte consists of 8 bits (bit is the smallest unit of data storage/transfer). Now, in science, mega, giga, tera, peta etc are used if a munber is multiplied with 1000 (subsequently). This means, (for say, voltage) 1 volt x 1000= 1 megavolt. 1 megavolt x 1000= 1 gigavolt 1 gigavolt x 1000=1 teravolt . . . . Now, in storage for computers, we use 1024 as the multiplier instead of 1000. It is because memory is calculated based on 2 (raised to power) n, and for n=10 (=1024) is comes out to be almost equal to the decimal system format. Now, the answer to the question, 2.5 megabytes = (say) m gigabytes. 1 gigabytes=1megabytes x 1024. so, 1 megabyte=1 gigabyte/1024. 2.5 megabyte=2.5gigabyte/1024. hence, 2.5megabytes=0.00244140625 gigabytes ~= 0.00244 gigabytes