Hex #557939 or rgb(85,121,57) in RGB space is the tint of olive. It has hue angle of 93.75 degrees, value = 47 and saturation = 53. #557939 can be obtained by mixing 2 colors: 1 drop of magenta, 2 drops of green.
Nearest safe hex - #666633. Below you can see the block with #557939 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #557939 to the mixer and play with it.