IsPrimeBLong

Private Sub Command1_Click()
Valu = Text1.Text
If Valu >= 2E+15 Then
MsgBox "The number is too big to be represented by the system!"
Exit Sub
End If
If Valu = 1 Then
MsgBox "1 is Not a prime number"
Exit Sub
End If
UpTo = Sqr(Valu)
z = (Valu / 2)
If z = Round(z, 0) Then Goto 1
For x = 3 To UpTo Step 2
z = (Valu / x)
If z = Round(z, 0) Then Goto 1
Next x
MsgBox "The number " & Valu & " is a prime number."
Exit Sub
1: MsgBox "The number " & Valu & " is Not a prime number, " & _
"divided by " & (Valu / z) & ". The answer will be " & z
End Sub