trying to make this program work, but it only works for the number 12..

Question

% this program will determine if an integer is prime and determine
% its prime factors

function MAIN
clear; clc;
% define number(s) to be checked, call function, and print output
N = 12;

[answer,primefactors] = primey(N);
fprintf('Is %i a prime? %s 
', N, answer)
fprintf('The primefactors of %i are: 
' , N)
fprintf('%i 
' , primefactors)
N = 12;
[answer,primefactors] = primey(N);
fprintf('Is %i a prime? %s 
', N, answer)
fprintf('The primefactors of %i are: 
' , N)
fprintf('%i 
' , primefactors)

end % end of function MAIN

function [answer,primefactors] = primey(N);

if mod(N,1)==0 & N/N==1
    answer= 'Yes';
else
    answer= 'No';
end

factors=[]
for k= 2:N-1
    
    if mod(N,k)==0 
        factors(k)=k; 
    end
   
      [a,b]= find(factors>0);
      b
    
      primefactors= [1:numel(b)-1];
      numel(b)
      
      for j= 1:numel(b)
          if mod(b(j),j)==0
              primefactors(j)= b(j)
          end
      end
      
end
      
end