Hex #66839f or rgb(102,131,159) in RGB space is the tint of blue. It has hue angle of 209.47 degrees, value = 62 and saturation = 36. #66839f can be obtained by mixing 4 colors: 2 drops of magenta, 4 drops of cyan, 4 drops of white, 5 drops of black.
Nearest safe hex - #669999. Below you can see the block with #66839f color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #66839f to the mixer and play with it.