Hex #663733 or rgb(102,55,51) in RGB space is the tint of red. It has hue angle of 4.71 degrees, value = 40 and saturation = 50. #663733 can be obtained by mixing 4 colors: 2 drops of yellow, 2 drops of magenta, 1 drop of blue, 5 drops of black.
Nearest safe hex - #663333. Below you can see the block with #663733 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #663733 to the mixer and play with it.