Hex #557b39 or rgb(85,123,57) in RGB space is the tint of olive. It has hue angle of 94.55 degrees, value = 48 and saturation = 54. #557b39 can be obtained by mixing 4 colors: 1 drop of yellow, 2 drops of green, 2 drops of white, 4 drops of black.
Nearest safe hex - #666633. Below you can see the block with #557b39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #557b39 to the mixer and play with it.