Hex #55666a or rgb(85,102,106) in RGB space is the tint of bluish cian. It has hue angle of 191.43 degrees, value = 42 and saturation = 20. #55666a can be obtained by mixing 4 colors: 2 drops of red, 3 drops of cyan, 2 drops of white, 5 drops of black.
Nearest safe hex - #666666. Below you can see the block with #55666a color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #55666a to the mixer and play with it.