This is the first "untouchable number," and it is the number of "exceptional" Lie groups. The complete graph with this many vertices is not planar according to Kuratowski's theorem. The Abel- Ruffini theorem states that this 
This is the first "untouchable number," and it is the number of "exceptional" Lie groups. The complete graph with this many vertices is not planar according to Kuratowski's theorem. The Abel- Ruffini theorem states that this is the smallest degree of radicals in a polynomial with no general solution. This is the second Fermat prime, the number of Platonic solids, and the fifth number of the Fibonacci sequence. For 10 points, name this number, which is written one-zero-one in binary, and equal to the square root of 25.
This is the first "untouchable number," and it is the number of "exceptional" Lie groups.
five