Hex #664b4d or rgb(102,75,77) in RGB space is the tint of red. It has hue angle of 355.56 degrees, value = 40 and saturation = 26. #664b4d can be obtained by mixing 4 colors: 2 drops of red, 1 drop of cyan, 2 drops of white, 5 drops of black.
Nearest safe hex - #663366. Below you can see the block with #664b4d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #664b4d to the mixer and play with it.