Console.WriteLine($"int? is {(IsNullable(typeof(int?)) ? "nullable" : "non nullable")} type"); Console.WriteLine($"int is {(IsNullable(typeof(int)) ? "nullable" : "non nullable")} type"); bool IsNullable(Type type) => Nullable.GetUnderlyingType(type) != null; // Output: // int? is nullable type // int is non nullable type