LengthOfRandomNumber

Dim intRandomNumber
intRandomNumber=fnRandomNumber(13)

MsgBox intRandomNumber

Function fnRandomNumber(LengthOfRandomNumber)

Dim sMaxVal : sMaxVal = ""
Dim iLength : iLength = LengthOfRandomNumber

'Find the maximum value for the given number of digits
For iL = 1 to iLength
sMaxVal = sMaxVal & "9"
Next
sMaxVal = Int(sMaxVal)

'Find Random Value
Randomize
iTmp = Int((sMaxVal * Rnd) + 1)
'Add Trailing Zeros if required
iLen = Len(iTmp)
fnRandomNumber1 = iTmp * (10 ^(iLength - iLen))
 fnRandomNumber=fnRandomNumber1
End Function