Hex #557840 or rgb(85,120,64) in RGB space is the tint of grass green. It has hue angle of 97.50 degrees, value = 47 and saturation = 47. #557840 can be obtained by mixing 4 colors: 4 drops of red, 3 drops of cyan, 4 drops of green, 1 drop of black.
Nearest safe hex - #666633. Below you can see the block with #557840 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #557840 to the mixer and play with it.