Hex #556940 or rgb(85,105,64) in RGB space is the tint of olive. It has hue angle of 89.27 degrees, value = 41 and saturation = 39. #556940 can be obtained by mixing 4 colors: 4 drops of red, 3 drops of cyan, 3 drops of green, 2 drops of black.
Nearest safe hex - #666633. Below you can see the block with #556940 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556940 to the mixer and play with it.