The Telephone numberNumber Theory Level 2
The telephone number of Bob's residence in the year 2000 is a 6-digit number. In 2006, the telephone company upgrades all the 6-digit numbers to 7-digit numbers by inserting the digit 8 between the first two digits. In 2014, they inserted a 2 to the start of the 7-digit number. Bob discovered that the 8-digit phone number is 81 times the original 6-digit number. What is his original number?