Multiplication, division and modulus operations on powers of 2 can be made much faster using bitwise operators.

1. Modulo
Finding the modulus is particularly expensive. This operation can be performed mush faster using the & operator, because
a % n == a & (n-1) where n is power of 2.

2. Division
Division by a power of 2 can done faster using the >> operator.
a / n == a >> m, where n = 2^m

3. Multiplication
This is similar to division, except, use left shift << operator
a * n == a <<m , n = 2^m