plz explain question 3 of quant daily target, why is the answer 661?

see, the largest 3 digit prime number is 997 and it will have only 2 mulitples which will get cancelled by 1000! each , but the next largest prime number is 661 which will have 3 multiples within 2000, two of which will get cancelled by 1000! but one will remain so, that's the answer.