Eight (8) is a positive integer one more than 7 and one less than 9.
8 is the second cube number, since it is equal to 23. It comes after 1 and before 27.
8 is the sixth Fibonacci number, between 5 and 13. In addition, it is the largest cubic Fibonacci number.
8 is the third power of two, between 4 and 16. As such it is used widely in computers, for instance in the octal system and the number of bits in a byte.
8 and 9 are the only non-trivial perfect powers numbers to differ by exactly 1. In addition 8 = 2^3 and 9 = 3^2.