Hex #663c39 or rgb(102,60,57) in RGB space is the tint of red. It has hue angle of 4.00 degrees, value = 40 and saturation = 44. #663c39 can be obtained by mixing 4 colors: 1 drop of red, 5 drops of magenta, 5 drops of green, 4 drops of black.
Nearest safe hex - #663333. Below you can see the block with #663c39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #663c39 to the mixer and play with it.