Hex #664d4a or rgb(102,77,74) in RGB space is the tint of red. It has hue angle of 6.43 degrees, value = 40 and saturation = 27. #664d4a can be obtained by mixing 4 colors: 5 drops of magenta, 5 drops of green, 1 drop of white, 4 drops of black.
Nearest safe hex - #666633. Below you can see the block with #664d4a color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #664d4a to the mixer and play with it.