Power of 2

n	2^n	approximate	Remarks
1	1	1	1 byte, 8 bits, 0xFF, java byte
2	4	4	4 bytes, 32 bits, 0xFFFFFFFF, java int, float
3	8	8	8 bytes, 64 bits, java long, double
4	16
5	32
6	64
7	128
8	256
9	512
10	1024	~1000	1KB, 1024
...
16	65536	65536	64KB
...
20	1,048,536	~1,000,000	1MB, 1024^2
...
30	1,073,741,824	~1,000,000,000	1GB, 1024^3
...
32	4,294,967,296	~4,300,000,000	4GB
...
40	1,099,511,627,776	~1,000,000,000,000	1TB, 1024^4

* 1 byte = 8 bits
* 1 kb = kilobit = 1000 bits = kbit
* 1 kB = kilobyte = 1000 bytes
* 1 KB = kibibyte = 1024 bytes = 2^10 bytes = KiB = KBytes