Hex #667b77 or rgb(102,123,119) in RGB space is the tint of greenish cian. It has hue angle of 168.57 degrees, value = 48 and saturation = 17. #667b77 can be obtained by mixing 4 colors: 1 drop of yellow, 1 drop of red, 2 drops of blue, 1 drop of cyan.
Nearest safe hex - #666666. Below you can see the block with #667b77 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #667b77 to the mixer and play with it.