Hex #508790 or rgb(80,135,144) in RGB space is the tint of bluish cian. It has hue angle of 188.44 degrees, value = 56 and saturation = 44. #508790 can be obtained by mixing 4 colors: 5 drops of magenta, 1 drop of blue, 5 drops of cyan, 5 drops of green.
Nearest safe hex - #669999. Below you can see the block with #508790 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #508790 to the mixer and play with it.