Hex #668633 or rgb(102,134,51) in RGB space is the tint of olive. It has hue angle of 83.13 degrees, value = 53 and saturation = 62. #668633 can be obtained by mixing 4 colors: 4 drops of yellow, 3 drops of blue, 1 drop of green, 2 drops of black.
Nearest safe hex - #669933. Below you can see the block with #668633 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #668633 to the mixer and play with it.