使用PHP Excel工作表显示加密字符串而不是我使用的数字

Question

I am using PHP Excel to make sheet in XLS format. There is an cell which is used to hold a number let's suppose 34567898 but when the sheet generates/downloaded it will became like 234E876 (like encrypted number). When I double-click on the sheet it converted into number same as I want.

I heard about to make cell format in text, so I change the format to text by this function

($objPHPExcel->getActiveSheet()
->getStyle('C1')
->getNumberFormat()
->setFormatCode(
    \PHPExcel_Style_NumberFormat::FORMAT_TEXT
);)

but it not works although when I check the format in sheet it is in text means function works but cell still showing the string 234E876.