Hello,
Your message is a bit confusing. From what I understand you are in Japan and trying to call a Singapore cell phone currently located in India. If this is correct you would dial: 010 65 followed by the cell number. I just tried dialing this number myself and I am getting a wrong number message. Moreover, according to my sources Singapore cell numbers can have the following two formats: 8??? ???? or 9??? ????. Your number starts with 5. Now, it is possible for some Singapore new cell numbers to start with 5, but I am not aware of such additions.