2717
number of digits: 4!
product of digits of product of digits of product of digits of product of digits: 4 !!
2*7*1*7=98; 9*8=72; 7*2=14; 1*4= 4 !!
Also:
(2+7)*(1+7)=9*8=72; 7*2=14; 1*4=4!!
Again:
sum of digits of sum of digits : 8
2+7+1+7=17; 1+7= 8 !!!
Also: (2+1)*(7+7)=3*14=42; 4*2 = 8!!