Hex #556939 or rgb(85,105,57) in RGB space is the tint of olive. It has hue angle of 85.00 degrees, value = 41 and saturation = 46. #556939 can be obtained by mixing 4 colors: 2 drops of yellow, 1 drop of red, 2 drops of cyan, 4 drops of black.
Nearest safe hex - #666633. Below you can see the block with #556939 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556939 to the mixer and play with it.