Checking if a number can be written as kth power of 2 using bitwise operations

PowerOf2Util4.java

/**
 * Problem: Given an integer, i, find whether it can be expressed as 2^k. Where k< i
 */
class PowerOf2Util4 {

    /**
     * Test
     */
    public static void main(String[] args) {
        int k=18;
        int input = 262144; // 2^18
        System.out.print( input + " is " + k + "th power of 2 ? " );
        System.out.println( isKthPowerOf2Number(input,k) );
    }

    /**
     * Time complexity: O(1)
     * Space complexity : 0(1)
     */
    private static boolean isKthPowerOf2Number(int input, int k){
        return ( (1<<k) == input) ;
    }
}