Hex #40391d or rgb(64,57,29) in RGB space is the tint of khaki. It has hue angle of 48.00 degrees, value = 25 and saturation = 55. #40391d can be obtained by mixing 4 colors: 3 drops of red, 2 drops of blue, 3 drops of green, 4 drops of black.
Nearest safe hex - #333333. Below you can see the block with #40391d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #40391d to the mixer and play with it.