Hex #669cbc or rgb(102,156,188) in RGB space is the tint of bluish cian. It has hue angle of 202.33 degrees, value = 74 and saturation = 46. #669cbc can be obtained by mixing 3 colors: 5 drops of blue, 1 drop of green, 4 drops of white.
Nearest safe hex - #6699cc. Below you can see the block with #669cbc color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669cbc to the mixer and play with it.