diff --git a/src/psij/executors/batch/batch_scheduler_executor.py b/src/psij/executors/batch/batch_scheduler_executor.py
index ebb691d0..0019a5d4 100644
--- a/src/psij/executors/batch/batch_scheduler_executor.py
+++ b/src/psij/executors/batch/batch_scheduler_executor.py
@@ -497,7 +497,7 @@ def _create_script_context(self, job: Job) -> Dict[str, object]:
     def _format_duration(self, d: timedelta) -> str:
         # the default is hh:mm:ss, with hh not limited to 24; this is the least ambiguous
         # choice
-        return '%s:%s:%s' % (d.total_seconds() // 3600, (d.seconds // 60) % 60, d.seconds % 60)
+        return '%s:%s:%s' % (int(d.total_seconds()) // 3600, (d.seconds // 60) % 60, d.seconds % 60)
 
     def _run_command(self, cmd: List[str]) -> str:
         res = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
diff --git a/src/psij/executors/batch/lsf.py b/src/psij/executors/batch/lsf.py
index f5dac7e3..274f081f 100644
--- a/src/psij/executors/batch/lsf.py
+++ b/src/psij/executors/batch/lsf.py
@@ -141,4 +141,4 @@ def get_list_command(self) -> List[str]:
     def _format_duration(self, d: timedelta) -> str:
         # https://www.ibm.com/docs/en/spectrum-lsf/10.1.0?topic=o-w-1:
         #   bsub -W [hour:]minute[/host_name | /host_model]
-        return "%s:%s" % (d.total_seconds() // 3600, (d.seconds // 60) % 60)
+        return "%s:%s" % (int(d.total_seconds()) // 3600, (d.seconds // 60) % 60)
diff --git a/tests/test_issue_435.py b/tests/test_issue_435.py
new file mode 100644
index 00000000..be145803
--- /dev/null
+++ b/tests/test_issue_435.py
@@ -0,0 +1,14 @@
+from datetime import timedelta
+
+from _test_tools import _get_executor_instance, _get_timeout, assert_completed
+from executor_test_params import ExecutorTestParams
+from psij import Job, JobSpec, JobAttributes
+
+
+def test_issue_435(execparams: ExecutorTestParams) -> None:
+    job = Job(JobSpec(executable='/bin/date', launcher=execparams.launcher,
+                      attributes=JobAttributes(duration=timedelta(seconds=3700.5))))
+    ex = _get_executor_instance(execparams, job)
+    ex.submit(job)
+    status = job.wait(timeout=_get_timeout(execparams))
+    assert_completed(job, status)