Hex #666578 or rgb(102,101,120) in RGB space is the tint of violet. It has hue angle of 243.16 degrees, value = 47 and saturation = 16. #666578 can be obtained by mixing 4 colors: 2 drops of yellow, 2 drops of magenta, 5 drops of blue, 1 drop of green.
Nearest safe hex - #666666. Below you can see the block with #666578 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #666578 to the mixer and play with it.