Hex #666933 or rgb(102,105,51) in RGB space is the tint of yellow. It has hue angle of 63.33 degrees, value = 41 and saturation = 51. #666933 can be obtained by mixing 4 colors: 2 drops of red, 3 drops of green, 2 drops of white, 3 drops of black.
Nearest safe hex - #666633. Below you can see the block with #666933 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #666933 to the mixer and play with it.