Bavaria is one of Germany’s safest states and it is very unlikely that you will ever feel unsafe here. The state has the lowest crime rates in Germany.
Nevertheless, as in any major city, you should always keep your wits about you, especially when walking on your own. Guard your personal belongings carefully in crowded places, particularly at big festivals like Oktoberfest or the Christmas markets. Also make sure you get a good lock to secure your bike before leaving it anywhere.
In case of emergencies, the numbers to call are:
110 for the police
112 for fire and emergency services