diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
index 7cc3d5c805..acb75f2ca1 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
@@ -122,7 +122,11 @@ class NumberToLocalizedStringTransformer implements DataTransformerInterface
             $value = str_replace(',', $decSep, $value);
         }
 
-        $result = $formatter->parse($value, \NumberFormatter::TYPE_DOUBLE, $position);
+        if (!strstr($value, $decSep) && PHP_INT_SIZE === 8) {
+            $result = $formatter->parse($value, \NumberFormatter::TYPE_INT64, $position);
+        } else {
+            $result = $formatter->parse($value, \NumberFormatter::TYPE_DOUBLE, $position);
+        }
 
         if (intl_is_failure($formatter->getErrorCode())) {
             throw new TransformationFailedException($formatter->getErrorMessage());
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
index e829871ec3..ef9c9738cb 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
@@ -433,4 +433,11 @@ class NumberToLocalizedStringTransformerTest extends \PHPUnit_Framework_TestCase
 
         $transformer->reverseTransform("12\xc2\xa0345,678foo");
     }
+
+    public function testReverseTransformBigint()
+    {
+        $transformer = new NumberToLocalizedStringTransformer(null, true);
+
+        $this->assertEquals(401657096594165125, (int) $transformer->reverseTransform((string) 401657096594165125));
+    }
 }