Hex #666600 or rgb(102,102,0) in RGB space is the tint of yellow. It has hue angle of 60.00 degrees, value = 40 and saturation = 100. #666600 can be obtained by mixing 4 colors: 2 drops of yellow, 2 drops of red, 3 drops of green, 3 drops of black.
Nearest safe hex - #666600. Below you can see the block with #666600 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #666600 to the mixer and play with it.