21659-28-9 Usage
Check Digit Verification of cas no
The CAS Registry Mumber 21659-28-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,1,6,5 and 9 respectively; the second part has 2 digits, 2 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 21659-28:
(7*2)+(6*1)+(5*6)+(4*5)+(3*9)+(2*2)+(1*8)=109
109 % 10 = 9
So 21659-28-9 is a valid CAS Registry Number.