Hex #158687 or rgb(21,134,135) in RGB space is the tint of cyan. It has hue angle of 180.53 degrees, value = 53 and saturation = 84. #158687 can be obtained by mixing 4 colors: 1 drop of red, 5 drops of blue, 3 drops of cyan, 3 drops of green.
Nearest safe hex - #009999. Below you can see the block with #158687 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #158687 to the mixer and play with it.