diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/CalcEngine/Functions/Text.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/CalcEngine/Functions/Text.cs
index dae361f..11a7c8b 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/CalcEngine/Functions/Text.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/CalcEngine/Functions/Text.cs
@@ -39,6 +39,7 @@
             ce.RegisterFunction("TRIM", 1, Trim); // Removes spaces from text
             ce.RegisterFunction("UPPER", 1, Upper); // Converts text to uppercase
             ce.RegisterFunction("VALUE", 1, Value); // Converts a text argument to a number
+            ce.RegisterFunction("HYPERLINK", 1, Hyperlink);
         }
 
         static object _Char(List<Expression> p)
@@ -195,5 +196,12 @@
         {
             return (string)p[0];
         }
+
+        static object Hyperlink(List<Expression> p)
+        {
+            String address = p[0];
+            String toolTip = p.Count == 2 ? p[1] : String.Empty;
+            return new XLHyperlink(address, toolTip);
+        }
     }
 }
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
index 463cd68..dcc5714 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -843,7 +843,8 @@
                 }
                 else if (cell.DataType == CellValues.Date)
                 {
-                    xlCell._cellValue = Double.Parse(cell.CellValue.Text, CultureInfo.InvariantCulture).ToString();
+                    if (!XLHelper.IsNullOrWhiteSpace(cell.CellValue.Text))
+                        xlCell._cellValue = Double.Parse(cell.CellValue.Text, CultureInfo.InvariantCulture).ToString();
                     xlCell._dataType = XLCellValues.DateTime;
                 }
                 else if (cell.DataType == CellValues.Boolean)
@@ -853,7 +854,8 @@
                 }
                 else if (cell.DataType == CellValues.Number)
                 {
-                    xlCell._cellValue = Double.Parse(cell.CellValue.Text, CultureInfo.InvariantCulture).ToString();
+                    if (!XLHelper.IsNullOrWhiteSpace(cell.CellValue.Text))
+                        xlCell._cellValue = Double.Parse(cell.CellValue.Text, CultureInfo.InvariantCulture).ToString();
                     var numberFormatId = ((CellFormat) (s.CellFormats).ElementAt(styleIndex)).NumberFormatId;
                     if (numberFormatId == 46U)
                         xlCell.DataType = XLCellValues.TimeSpan;