Hex #556e39 or rgb(85,110,57) in RGB space is the tint of olive. It has hue angle of 88.30 degrees, value = 43 and saturation = 48. #556e39 can be obtained by mixing 4 colors: 1 drop of yellow, 2 drops of red, 3 drops of blue, 3 drops of green.
Nearest safe hex - #666633. Below you can see the block with #556e39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556e39 to the mixer and play with it.