Various people, including Donald Trump, have suggested that Obama was not born in the U.S. and may be a Muslim. The former claim, while it may be false, is not absurd—there is no obvious way of being certain of the details of the birth more than fifty years ago of someone of no particular prominence. The claim he is a Muslim, on the other hand, has at least two serious problems.
One of the binding obligations of Islam is to pray five times a day, in a specified manner (with some possible variations), at specified times. If Obama has managed to do that through most of two terms without anyone noticing, he is a very talented man. A second binding obligation is to fast through the month of Ramadan—neither eat nor drink in daylight hours.