Hex #663333 or rgb(102,51,51) in RGB space is the tint of red. It has hue angle of 0.00 degrees, value = 40 and saturation = 50. #663333 can be obtained by mixing 3 colors: 1 drop of red, 1 drop of white, 3 drops of black.
Nearest safe hex - #663333. Below you can see the block with #663333 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #663333 to the mixer and play with it.