98 × 98 = 9604

The place value of 9 is = 9000, and the place value of 3 is = 30.
9000 - 30 = 8970.

19, is a prime number less than 70.

53+59+61+67+71+73+79+83+89 = 635.

unit digit = 7 × 5 × 8 × 3 × 9 = 140 =0

2 is the only number that is prime number.