Hex #55578f or rgb(85,87,143) in RGB space is the tint of violet. It has hue angle of 237.93 degrees, value = 56 and saturation = 41. #55578f can be obtained by mixing 3 colors: 1 drop of yellow, 1 drop of magenta, 4 drops of blue.
Nearest safe hex - #666699. Below you can see the block with #55578f color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #55578f to the mixer and play with it.