Facts About Numbers Prime number p: ▣p is an integer p≥2 The only divisors of p are 1 and p ●Examples ▣2,7，l9 are primes -3,0,1,6 are not primes Prime decomposition of a positive integer n: n=p1e1×.Xpxk ●Example: 口200=23×52 Fundamental Theorem of Arithmetic The prime decomposition of a positive integer is unique 3/31/2016 Cryptography 11Facts About Numbers  Prime number p:  p is an integer  p  2  The only divisors of p are 1 and p  Examples  2, 7, 19 are primes  -3, 0, 1, 6 are not primes  Prime decomposition of a positive integer n: n = p1 e 1  …  pk e k  Example:  200 = 2 3  5 2 Fundamental Theorem of Arithmetic The prime decomposition of a positive integer is unique 3/31/2016 Cryptography 11