Hex #669caa or rgb(102,156,170) in RGB space is the tint of bluish cian. It has hue angle of 192.35 degrees, value = 67 and saturation = 40. #669caa can be obtained by mixing 4 colors: 1 drop of yellow, 1 drop of magenta, 1 drop of blue, 2 drops of cyan.
Nearest safe hex - #669999. Below you can see the block with #669caa color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669caa to the mixer and play with it.