Hex #178cd1 or rgb(23,140,209) in RGB space is the tint of bluish cian. It has hue angle of 202.26 degrees, value = 82 and saturation = 89. #178cd1 can be obtained by mixing 3 colors: 1 drop of magenta, 5 drops of blue, 5 drops of cyan.
Nearest safe hex - #0099cc. Below you can see the block with #178cd1 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #178cd1 to the mixer and play with it.