Hex #667e80 or rgb(102,126,128) in RGB space is the tint of cyan. It has hue angle of 184.62 degrees, value = 50 and saturation = 20. #667e80 can be obtained by mixing 3 colors: 1 drop of cyan, 4 drops of white, 5 drops of black.
Nearest safe hex - #666699. Below you can see the block with #667e80 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #667e80 to the mixer and play with it.