title: Project Euler: #8
body: <p>When trying to answer this problem:</p>
  
  <blockquote>
    <p>The four adjacent digits in the 1000-digit number that have the
    greatest product are 9 × 9 × 8 × 9 = 5832.</p>
    
    <p>73167176531330624919225119674426574742355349194934
    96983520312774506326239578318016984801869478851843
    85861560789112949495459501737958331952853208805511
    12540698747158523863050715693290963295227443043557
    66896648950445244523161731856403098711121722383113
    62229893423380308135336276614282806444486645238749
    30358907296290491560440772390713810515859307960866
    70172427121883998797908792274921901699720888093776
    65727333001053367881220235421809751254540594752243
    52584907711670556013604839586446706324415722155397
    53697817977846174064955149290862569321978468622482
    83972241375657056057490261407972968652414535100474
    82166370484403199890008895243450658541227588666881
    16427171479924442928230863465674813919123162824586
    17866458359124566529476545682848912883142607690042
    24219022671055626321111109370544217506941658960408
    07198403850962455444362981230987879927244284909188
    84580156166097919133875499200524063689912560717606
    05886116467109405077541002256983155200055935729725
    71636269561882670428252483600823257530420752963450 </p>
    
    <p>Find the thirteen
    adjacent digits in the 1000-digit number that have the greatest
    product. What is the value of this product?</p>
  </blockquote>
  
  <p>I get 2091059712 however Euler says the answer is incorrect is there anything I may be doing incorrectly?</p>
  
  <pre><code>public class LargestProductThirteen{
    public static void main( String[] args ) {
      final String num = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
      long greatestProduct = 0;
      for (int i = 0; i &lt; num.length() - 12; i++) {
          long sum = Character.getNumericValue(num.charAt(i))* 
              Character.getNumericValue(num.charAt(i+1))* 
              Character.getNumericValue(num.charAt(i+2))* 
              Character.getNumericValue(num.charAt(i+3))* 
              Character.getNumericValue(num.charAt(i+4))* 
              Character.getNumericValue(num.charAt(i+5))* 
              Character.getNumericValue(num.charAt(i+6))* 
              Character.getNumericValue(num.charAt(i+7))* 
              Character.getNumericValue(num.charAt(i+8))* 
              Character.getNumericValue(num.charAt(i+9))* 
              Character.getNumericValue(num.charAt(i+10))* 
              Character.getNumericValue(num.charAt(i+11))* 
              Character.getNumericValue(num.charAt(i+12));
          if (sum &gt; greatestProduct)
              greatestProduct = sum;
      }
      System.out.println(greatestProduct);
    }
  }
  </code></pre>