Hex #00878a or rgb(0,135,138) in RGB space is the tint of cyan. It has hue angle of 181.30 degrees, value = 54 and saturation = 100. #00878a can be obtained by mixing 4 colors: 3 drops of blue, 5 drops of cyan, 2 drops of green, 3 drops of black.
Nearest safe hex - #009999. Below you can see the block with #00878a color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #00878a to the mixer and play with it.