7 is the sole number D for which the equation 2n − D = x2 has over two alternatives for n and x normal. Particularly, the equation 2n − 7 = x2 is known as the Ramanujan–Nagell equation. Jahannam has 7 gates which can be open up always. (Qur’an – https://ericap345fvj5.wikitelevisions.com/user