Hex #664780 or rgb(102,71,128) in RGB space is the tint of purple. It has hue angle of 272.63 degrees, value = 50 and saturation = 45. #664780 can be obtained by mixing 4 colors: 1 drop of red, 3 drops of magenta, 3 drops of cyan, 3 drops of black.
Nearest safe hex - #663399. Below you can see the block with #664780 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #664780 to the mixer and play with it.