Why mobile number have 10 digit?

Answer 1

Actually, it doesn't. At least, it is not 10 digits all over the world. For example, in Bolivia, the mobile phone number has only 8 digits. The number of digits required (for any particular country) can depend on the following:

• The number of mobile phones (or similar devices) used. If in some country you have, say, 5 million mobile devices, you need at least seven digits.
• Mobile numbers may have to start with certain digits. This may require an additional digit. In the above example, if in a country all mobile phone numbers start with 6, 7 or 8, then 7 digits are no longer enough - the minimum requirement is 8 digits.
• The numbers may be organized so that the first few digits identify the phone company, or the geographical region. This also tends to increase the number of digits, since some areas will have few numbers, while others will have many.

Answer 2

i think each digit shows the specific region code.......................