Use the getNumScatterers object function to find the number of scatterers on a bicyclist with 25 spokes. Create the backscatterBicyclist object and then call getNumScatterers.
fc = 77e9;
bicyclist = backscatterBicyclist( ...'OperatingFrequency',fc,'NumWheelSpokes',25, ...'InitialPosition',[5;0;0]);
N = getNumScatterers(bicyclist)