Question

without actual division show 7777 , 77077 divisible by 7

Answer 1

Try using the divisibility rule for 7. 
Divisibility rule for 7: To find out if a number is divisible by seven, take the last digit, double it, and subtract it from the rest of the number. If you get an answer divisible by 7 (including zero), then the original number is divisible by seven.