Hex #555787 or rgb(85,87,135) in RGB space is the tint of violet. It has hue angle of 237.60 degrees, value = 53 and saturation = 37. #555787 can be obtained by mixing 4 colors: 1 drop of magenta, 4 drops of blue, 3 drops of white, 4 drops of black.
Nearest safe hex - #666699. Below you can see the block with #555787 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #555787 to the mixer and play with it.