Hex #666333 or rgb(102,99,51) in RGB space is the tint of yellow. It has hue angle of 56.47 degrees, value = 40 and saturation = 50. #666333 can be obtained by mixing 4 colors: 3 drops of red, 4 drops of green, 3 drops of white, 5 drops of black.
Nearest safe hex - #666633. Below you can see the block with #666333 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #666333 to the mixer and play with it.