Hex #555779 or rgb(85,87,121) in RGB space is the tint of violet. It has hue angle of 236.67 degrees, value = 47 and saturation = 30. #555779 can be obtained by mixing 4 colors: 1 drop of red, 4 drops of blue, 3 drops of white, 4 drops of black.
Nearest safe hex - #666666. Below you can see the block with #555779 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #555779 to the mixer and play with it.