Hex #878d91 or rgb(135,141,145) in RGB space is the tint of blue. It has hue angle of 204.00 degrees, value = 57 and saturation = 7. #878d91 can be obtained by mixing 4 colors: 4 drops of magenta, 3 drops of blue, 5 drops of green, 5 drops of white.
Nearest safe hex - #999999. Below you can see the block with #878d91 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #878d91 to the mixer and play with it.