diff --git a/llarp/util/bencode.cpp b/llarp/util/bencode.cpp
index 1200834db..058054a67 100644
--- a/llarp/util/bencode.cpp
+++ b/llarp/util/bencode.cpp
@@ -75,7 +75,11 @@ bencode_write_bytestring(llarp_buffer_t* buff, const void* data, size_t sz)
 bool
 bencode_write_uint64(llarp_buffer_t* buff, uint64_t i)
 {
+#if (__APPLE__ && __MACH__)
+  if(!buff->writef("i%llu", i))
+#else
   if(!buff->writef("i%lu", i))
+#endif
   {
     return false;
   }