create table mst_reg 
(id int not null identity(1,1),
Name varchar(80),
Lastname varchar(80),
Fathername varchar(80),
Qualifiaction varchar(80),
Emailid varchar(80),
Phno int
)


insert into mst_reg values('aqib','javid','nijamudeen','BTechIT','aqib55@live.com',965557017796)


while executing the query to insert the data ito the table it shows 
"
Msg 8115, Level 16, State 2, Line 1
Arithmetic overflow error converting expression to data type int.
The statement has been terminated." please help me

insert into mst_reg values('aqib','javid','nijamudeen','BTechIT','aqib55@live.com',655456886)

will work..check int length then insert.

An integer data type can store values between -2,147,483,648 and 2,147,483,647 (https://msdn.microsoft.com/en-us/library/ms187745.aspx).  The Phno value exceeds this range.  If this is a telephone number, I suggest you use varchar instead.