Is the number written in Scientific notation. if not explain

If written exactly as shown, then no. But 50.1 x 10^{3} would be correct scientific notation and that is probably what you were really asking about. In normalized scientific notation, the first number is selected to have an absolute value between
1 and 10. So, to write this number in normalized scientific notation, you would write 5.01 x 10^{4}. (We divide 50.1 by 10, so have to multiply 10^{3} by 10 which becomes 10^{4}.) Additionally, you could write 50.1E3 if using scientific
E notation which is often used on calculators. And to cover all the bases, this number is 50,100. (Write 50.1 as 50.100 and then move the decimal point 3 places to the right to reflect multiplication by 10^{3} which is 1,000.) Hope that helps!