diff --git a/strings/base_extern.h b/strings/base_extern.h
index d78b9c3f1..39af7e557 100644
--- a/strings/base_extern.h
+++ b/strings/base_extern.h
@@ -76,8 +76,8 @@ extern "C"
     int32_t __stdcall WINRT_IMPL_SetThreadpoolThreadMinimum(winrt::impl::ptp_pool pool, uint32_t value) noexcept;
     void     __stdcall WINRT_IMPL_CloseThreadpool(winrt::impl::ptp_pool pool) noexcept;
 
-    int32_t __stdcall WINRT_IMPL_CanUnloadNow() noexcept;
-    int32_t __stdcall WINRT_IMPL_GetActivationFactory(void* classId, void** factory) noexcept;
+    int32_t __stdcall WINRT_CanUnloadNow() noexcept;
+    int32_t __stdcall WINRT_GetActivationFactory(void* classId, void** factory) noexcept;
 }
 
 #ifdef _M_HYBRID
diff --git a/strings/base_string.h b/strings/base_string.h
index 933f73f25..5f389a314 100644
--- a/strings/base_string.h
+++ b/strings/base_string.h
@@ -75,7 +75,7 @@ namespace winrt::impl
     inline shared_hstring_header* precreate_hstring_on_heap(uint32_t length)
     {
         WINRT_ASSERT(length != 0);
-        uint64_t bytes_required = sizeof(shared_hstring_header) + sizeof(wchar_t) * length;
+        uint64_t bytes_required = static_cast<uint64_t>(sizeof(shared_hstring_header)) + static_cast<uint64_t>(sizeof(wchar_t)) * static_cast<uint64_t>(length);
 
         if (bytes_required > UINT_MAX)
         {