Hex #667c7d or rgb(102,124,125) in RGB space is the tint of cyan. It has hue angle of 182.61 degrees, value = 49 and saturation = 18. #667c7d can be obtained by mixing 4 colors: 1 drop of red, 5 drops of magenta, 4 drops of cyan, 5 drops of green.
Nearest safe hex - #666666. Below you can see the block with #667c7d color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #667c7d to the mixer and play with it.