Color c = new Color(0x15,0x89,0xFF);

// Get saturation and brightness.
float[] hsbVals = new float[3];
Color.RGBtoHSB(c.getRed(),c.getGreen(),c.getBlue(),hsbVals);

// Pass .5 (= 180 degrees) as HUE
c = new Color(Color.HSBtoRGB(0.5f,hsbVals[1],hsbVals[2]));