Question

Show that 571 is a prime number.

Answer 1

$$\begin{gathered} \mathrm{Since}571\mathrm{has}\mathrm{no}\mathrm{factor}\mathrm{other}\mathrm{than}1\mathrm{and}571.\mathrm{Therefore}571\mathrm{is}\mathrm{a}\mathrm{prime}\mathrm{number}. \\ \mathrm{Now}, \\ \sqrt{571}=23.8956\mathrm{and}\mathrm{any}\mathrm{number}\mathrm{less}\mathrm{than}23\mathrm{except}1\mathrm{does}\mathrm{not}\mathrm{divisible}\mathrm{by}571.\mathrm{So}571\mathrm{is}\mathrm{a}\mathrm{prime}\mathrm{number}. \end{gathered}$$