Hex #555439 or rgb(85,84,57) in RGB space is the tint of yellow. It has hue angle of 57.86 degrees, value = 33 and saturation = 33. #555439 can be obtained by mixing 3 colors: 1 drop of red, 1 drop of blue, 1 drop of green.
Nearest safe hex - #666633. Below you can see the block with #555439 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #555439 to the mixer and play with it.