Formula concatenate excel in c #

I'm applying a concatenation formula using the excel tools for c #, the formula I'm trying to apply is to concatenate

Code C #

Sum_RangeResuTot.Formula = "=CONCATENATE('LA SUMA ES',SUM(F" + (i + 5).ToString() + ":F" + (i + 15).ToString();

Excel Code

=CONCATENAR("LA SUMA ES ";SUMA(F74:F84))

But when executing the code, I get the following error,

System.Runtime.InteropServices.COMException (0x800A03EC): Excepción de HRESULT: 0x800A03EC
   en System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
   en Microsoft.Office.Interop.Excel.Range.set_Formula(Object value)
   en Sisrol_Net.FormMain.semanalToolStripMenuItem7_Click(Object sender, EventArgs e) en c:\Users\Robert\Google Drive\RCER\Sisrol-Net\Sisrol-Net\FormMain.cs:línea 13598}

With which I would be indicating that I have an error in the formula and I get that error message, if you could help me in solving this error I would be very grateful.

Thanks in advance for your help.