diff --git a/src/c/main.d b/src/c/main.d
index ce605aeaa..9ec6f786d 100755
--- a/src/c/main.d
+++ b/src/c/main.d
@@ -91,7 +91,7 @@ cl_fixnum ecl_option_values[ECL_OPT_LIMIT+1] = {
 #if ECL_FIXNUM_BITS <= 32
         1024*1024*1024, /* ECL_OPT_HEAP_SIZE */
 #else
-        4024*1024*1024, /* ECL_OPT_HEAP_SIZE */
+        4294967296L,    /* ECL_OPT_HEAP_SIZE */
 #endif
         1024*1024,      /* ECL_OPT_HEAP_SAFETY_AREA */
         0,              /* ECL_OPT_THREAD_INTERRUPT_SIGNAL */