No, it is of a mass that according to our still standing understanding of astrophysics, is impossible to create by the collapse of "a single star". But you can

No, it is of a mass that according to our still standing understanding of astrophysics, is impossible to create by the collapse of "a single star". But you can very well have this mass by the colapse of two black holes, or by one black hole that ends up consuming one or more stars nearby in due time.