Hex #155b80 or rgb(21,91,128) in RGB space is the tint of bluish cian. It has hue angle of 200.75 degrees, value = 50 and saturation = 84. #155b80 can be obtained by mixing 4 colors: 1 drop of magenta, 2 drops of blue, 4 drops of cyan, 5 drops of black.
Nearest safe hex - #006699. Below you can see the block with #155b80 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #155b80 to the mixer and play with it.