Help prime co prime

help im trying to output prime and coprime AND NEITHER DEPENDING ON THE NUMBERand its not working
i have been trying for hours and its not working
swift help would be appreciated

Function IsPrime(TestPrime As Long)
    Dim TestNum As Long
    Dim checkPrime As Boolean
    Dim TestLimit As Long
    If TestPrime Mod 2 = 0 Then Exit Function
    TestNum = 3
    TestLimit = TestPrime
    Do While TestLimit > TestNum
    If TestPrime Mod TestNum = 0 Then
    Exit Function
    End If
    TestLimit = TestPrime \ TestNum
    TestNum = TestNum + 2
    Loop
    checkPrime = True
    
    
     If checkPrime = True Then
     IsPrime = "prime"
     Else: IsPrime = "coprime"
     End If
    
     If TestPrime = 1 Then
     IsPrime = "neither"
     End If
     
     
  
    
End Function