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# Power of two

A number is said to be a **power of two** when its factorization gives only twos, or when it can be expressed as a multiplication of only twos (like 2 × 2 × 2 × ...). They are normally represented as [math]\displaystyle{ 2^n }[/math] where n is the exponent.

Powers of two are very important in computer science, as they are the base for the binary system, used by computers when considering bits and bytes. Sometimes prefixes are reinterpreted to refer to those powers, as in 1 kilobyte = 2^{10} = 1024. To avoid confusion, in 1998 a set of binary prefixes was introduced. The prefix for multiples of 1024 is kibi-, so 1024 bytes = 1 kibibyte. 1024^{2} bytes = 1 mebibyte, 1024^{3} bytes = 1 gibibyte, and so on.