I wish I could tell you what this plant is - but I can tell you what it isn't - it is not Mammillaria magnimamma or any of its various forms. Your plant has very clearly differentiated radials and centrals, 6 or 7 radials and 2 centrals, dark tipped - Sorry Del.
The large angled tubercles should give me a better idea, and my thoughts are going to forms of Mammillaria mystax or possibly Mammillaria sartorii. Both of these have pink flowers, but I am by no means certain that either of those two are right.
Hopefully others might have a better idea.