A much-debated topic is the role of universities in the prosperity of cities and regions. Two major problems arise. First, what is a reliable measurement of prosperity? And second, what are the characteristics, particularly research performance, of a university that matter? I focus on this research question: Is there a significant relation between having a university and a city’s socioeconomic strength? And if so, what are the determining indicators of a university; for instance, how important is scientific collaboration? What is the role of scientific quality measured by citation impact? Does the size of a university, measured in number of publications or in number of students matter? I compiled a database of city and university data: gross urban product and population data of nearly 200 German cities and 400 districts. University data are derived from the Leiden Ranking 2020 and supplemented with data on the number of students. The socioeconomic strength of a city is determined using the urban scaling methodology. My study shows a significant relation between the presence of a university in a city and its socioeconomic indicators, particularly for larger cities, and that this is especially the case for universities with higher values of their output, impact and collaboration indicators.