Hex #556d55 or rgb(85,109,85) in RGB space is the tint of green. It has hue angle of 120.00 degrees, value = 43 and saturation = 22. #556d55 can be obtained by mixing 4 colors: 2 drops of red, 2 drops of cyan, 1 drop of green, 1 drop of black.
Nearest safe hex - #666666. Below you can see the block with #556d55 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #556d55 to the mixer and play with it.