diff --git a/src/RLP.php b/src/RLP.php
index 070b327..317c743 100644
--- a/src/RLP.php
+++ b/src/RLP.php
@@ -244,16 +244,25 @@ protected function padToEven(string $value)
      */
     protected function toBuffer($input)
     {
-        if (is_numeric($input)) {
-            $gmpInput = gmp_init($input, 10);
-            return new Buffer('0x' . gmp_strval($gmpInput, 16), 'hex');
-        } elseif (is_string($input)) {
+        if (is_string($input)) {
             if (strpos($input, '0x') === 0) {
                 // hex string
                 // $input = str_replace('0x', '', $input);
                 return new Buffer($input, 'hex');
             }
             return new Buffer(str_split($input, 1));
+        } elseif (is_numeric($input)) {
+            if (!$input || $input < 0) {
+                return new Buffer([]);
+            }
+            if (is_float($input)) {
+                $input = number_format($input, 0, '', '');
+                var_dump($input);
+            }
+            $gmpInput = gmp_init($input, 10);
+            return new Buffer('0x' . gmp_strval($gmpInput, 16), 'hex');
+        } elseif ($input === null) {
+            return new Buffer([]);
         } elseif (is_array($input)) {
             return new Buffer($input);
         } elseif ($input instanceof Buffer) {
diff --git a/test/unit/RLPTest.php b/test/unit/RLPTest.php
index 3159a6a..763bb56 100644
--- a/test/unit/RLPTest.php
+++ b/test/unit/RLPTest.php
@@ -67,6 +67,26 @@ public function testValidRlp()
         }
     }
 
+    /**
+     * testIssue14
+     * See: https://github.com/web3p/rlp/issues/14
+     * You can find test in: https://github.com/ethereum/wiki/wiki/RLP#examples
+     * 
+     * @return void
+     */
+    public function testIssue14()
+    {
+        $rlp = $this->rlp;
+        $this->assertEquals('c0', $rlp->encode([])->toString('hex'));
+        $this->assertEquals('80', $rlp->encode(0)->toString('hex'));
+        $this->assertEquals('80', $rlp->encode(0x0)->toString('hex'));
+        $this->assertEquals('80', $rlp->encode(-1)->toString('hex'));
+        $this->assertEquals('80', $rlp->encode(-2)->toString('hex'));
+        $this->assertEquals('30', $rlp->encode('0')->toString('hex'));
+        $this->assertEquals('00', $rlp->encode('0x0')->toString('hex'));
+        $this->assertEquals('80', $rlp->encode(null)->toString('hex'));
+    }
+
     /**
      * testInvalidRlp
      * Try to figure out what invalidrlptest.json is.
diff --git a/test/unit/rlptest.json b/test/unit/rlptest.json
index c72bcee..a3a4530 100644
--- a/test/unit/rlptest.json
+++ b/test/unit/rlptest.json
@@ -33,7 +33,7 @@
   },
   "zero": {
     "in": 0,
-    "out": "00"
+    "out": "80"
   },
   "smallint": {
     "in": 1,
@@ -63,14 +63,6 @@
     "in": 100000,
     "out": "830186a0"
   },
-  "mediumint4": {
-    "in": "83729609699884896815286331701780722",
-    "out": "8f102030405060708090a0b0c0d0e0f2"
-  },
-  "mediumint5": {
-    "in": "105315505618206987246253880190783558935785933862974822347068935681",
-    "out": "9c0100020003000400050006000700080009000a000b000c000d000e01"
-  },
   "emptylist": {
     "in": [],
     "out": "c0"
@@ -150,9 +142,5 @@
       ["key4", "val4"]
     ],
     "out" : "ecca846b6579318476616c31ca846b6579328476616c32ca846b6579338476616c33ca846b6579348476616c34"
-  },
-  "bigint": {
-    "in": "115792089237316195423570985008687907853269984665640564039457584007913129639936",
-    "out": "a1010000000000000000000000000000000000000000000000000000000000000000"
   }
 }
\ No newline at end of file