AWS + CakePhp - Spreadsheet_Excel_Reader：带有负值的Excel导入在mysql中保存了一些垃圾值

I have a CakePHP web application hosted on AWS, where I have excel import functionality using Spreadsheet_Excel_Reader class. But, I am stuck in strange issue, when I import excel with amount "-999998" value it saved exact value in mysql, but when I have "-999999" value it saved some garbage value like '1072741825'.

But with same scenarios in local (wamp) their is not issue.

Note : when I set excel cell format as "Text" it works fine, but with format "Number" it fail.

Thanks in advance.