diff --git a/test/test_convert.cpp b/test/test_convert.cpp
index 41825a5b..2e12df54 100644
--- a/test/test_convert.cpp
+++ b/test/test_convert.cpp
@@ -110,7 +110,7 @@ struct convert<person>
 	{
 		if (!is_valid(isolate, value))
 		{
-			throw std::runtime_error("excpected object");
+			throw std::runtime_error("expected object");
 		}
 
 		v8::HandleScope scope(isolate);
@@ -153,6 +153,8 @@ void test_convert()
 #ifdef WIN32
 	test_string_conv(isolate, L"qaz");
 #endif
+	// numeric string
+	test_string_conv(isolate, "0");
 
 	const std::vector<int> vector{ 1, 2, 3 };
 	test_conv(isolate, vector);
@@ -170,7 +172,7 @@ void test_convert()
 	test_conv(isolate, std::map<char, int>{ { 'a', 1 }, { 'b', 2 }, { 'c', 3 } });
 	test_conv(isolate, std::multimap<int, int>{ { 1, -1 }, { 2, -2 } });
 	test_conv(isolate, std::unordered_map<char, std::string>{ { 'x', "1" }, { 'y', "2" } });
-	test_conv(isolate, std::unordered_multimap<std::string, int>{ { "a", 1 }, { "b", 2 } });
+	test_conv(isolate, std::unordered_multimap<std::string, int>{ { "0", 0 }, { "a", 1 }, { "b", 2 } });
 
 	check_eq("initializer list to array",
 		v8pp::from_v8<std::vector<int>>(isolate, v8pp::to_v8(isolate, { 1, 2, 3 })), vector);
diff --git a/v8pp/convert.hpp b/v8pp/convert.hpp
index f7535d48..af2a8b79 100644
--- a/v8pp/convert.hpp
+++ b/v8pp/convert.hpp
@@ -60,7 +60,7 @@ struct convert<String, typename std::enable_if<detail::is_string<String>::value>
 
 	static bool is_valid(v8::Isolate*, v8::Local<v8::Value> value)
 	{
-		return !value.IsEmpty() && value->IsString();
+		return !value.IsEmpty() && (value->IsString() || value->IsNumber());
 	}
 
 	static from_type from_v8(v8::Isolate* isolate, v8::Local<v8::Value> value)