Hex #667880 or rgb(102,120,128) in RGB space is the tint of bluish cian. It has hue angle of 198.46 degrees, value = 50 and saturation = 20. #667880 can be obtained by mixing 4 colors: 3 drops of red, 4 drops of cyan, 1 drop of white, 2 drops of black.
Nearest safe hex - #666699. Below you can see the block with #667880 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #667880 to the mixer and play with it.