Hex #666d77 or rgb(102,109,119) in RGB space is the tint of blue. It has hue angle of 215.29 degrees, value = 47 and saturation = 14. #666d77 can be obtained by mixing 3 colors: 1 drop of blue, 4 drops of white, 5 drops of black.
Nearest safe hex - #666666. Below you can see the block with #666d77 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #666d77 to the mixer and play with it.