Get a fidget spinner, take out the three parts on the outside. Fit your middle finger through two of the holes and have the third sticking out. It'll hurt like fuck to get hit with, and I've tested it myself on my own body. I've also hit a wooden table, full force, with it and it didn't really hurt.
It's essentially a legal pair of brass knuckles, and no one can complain about you having them.
I recommend also keeping a pair of pens with you. If the idiots attack, pull out the pens from your pocket and stab them. Aim for the eyes, face, and throat, as the pen is likely to be most effective there.
Make sure that if you do any of these things, you do them in an area where there are witnesses who can testify you were being attacked.
Also, if I were you, I would walk slowly, trying not to make much noise. Just keep your ears open, as these niggers like to attack from behind by running up. If you hear one of them running up behind you, don't turn around immediately. Wait until they are close and about to hit you, and then turn and stab. Their own momentum, plus your stab, and the sharp point, will really fucking hurt. Might even take the one guy out of the fight if its bad enough.
It is also important you don't let them surround you, and that you make sure you don't let them get you cornered. Focus on taking them out individually. You want to hurt them bad enough that they can't fight, so don't just go for a body blow or some superficial injury. Do something that causes real pain or incapacitates them. I recommend aiming for the throat, the testicles, or the eyes. Very good, soft targets that can do serious damage.
If you hurt them bad enough, they'll run away. Niggers are stronger, but like any predatory animal, if the prey fights back and manages to injure them, they'll pick another target. You don't need to be stronger than them to win.
Last thing: make sure you report it and have proof. Niggers may show up with weapons in the future, so get them arrested.