8 Wikipedia. In mathematics. 8 is: a composite number, its proper divisors being 1, 2, and 4.It is twice 4 or four times 2. a power of two, being 2 3 (two cubed), and is the first number of the form p 3, p being an integer greater than 1.; the first number which is neither prime nor semiprime.; the base of the octal number system, which is mostly used with computers.In octal, one digit ...