
A long
integer is a number that can be used for a variable
involving greater numbers than integers. To declare a variable that
would hold such a large number, use the Long data type. Here
is an example:

Sub Exercise()
Dim Population As Long
End Sub
The type character for the Long data type is @. The
above variable could be declared as:
Sub Exercise()
Dim Population@
End Sub
A Long variable can store a value between – 2,147,483,648
and 2,147,483,647 (remember that the commas are used to make the numbers
easy to read; do not be used them in your code). Therefore, after
declaring a Long variable, you can assign it a number in that
range.
To convert a value to a long integer, call CLng()
using the following formula:
Number = CLng(Value to Convert)
To convert a value to long, enter it in the
parentheses of CLng().