diff --git a/lib/PhpParser/PrettyPrinter/Standard.php b/lib/PhpParser/PrettyPrinter/Standard.php
index 46cebce..45fe741 100644
--- a/lib/PhpParser/PrettyPrinter/Standard.php
+++ b/lib/PhpParser/PrettyPrinter/Standard.php
@@ -98,7 +98,7 @@ class Standard extends PrettyPrinterAbstract
         $stringValue = (string) $node->value;
 
         // ensure that number is really printed as float
-        return ctype_digit($stringValue) ? $stringValue . '.0' : $stringValue;
+        return preg_match('/^-?[0-9]+$/', $stringValue) ? $stringValue . '.0' : $stringValue;
     }
 
     // Assignments
@@ -735,4 +735,4 @@ class Standard extends PrettyPrinterAbstract
             return $this->p($node);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/test/code/prettyPrinter/numbers.test b/test/code/prettyPrinter/numbers.test
new file mode 100644
index 0000000..292919b
--- /dev/null
+++ b/test/code/prettyPrinter/numbers.test
@@ -0,0 +1,35 @@
+Number literals
+-----
+<?php
+
+0;
++0;
+-0;
+0.0;
+-0.0;
+42;
+-42;
+42.0;
+-42.0;
+42.5;
+-42.5;
+1e42;
+-1e42;
+1e1000;
+-1e1000;
+-----
+0;
++0;
+-0;
+0.0;
+-0.0;
+42;
+-42;
+42.0;
+-42.0;
+42.5;
+-42.5;
+1.0E+42;
+-1.0E+42;
+INF;
+-INF;
\ No newline at end of file