From 98f2c918686c2f7de6581e82cbb5a08343149d19 Mon Sep 17 00:00:00 2001
From: nrebena <49879400+nrebena@users.noreply.github.com>
Date: Mon, 21 Sep 2020 00:34:17 +0200
Subject: [PATCH 1/3] BUG: Fix hour for Period with ordinal >= 2562048

---
 pandas/_libs/tslibs/period.pyx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/_libs/tslibs/period.pyx b/pandas/_libs/tslibs/period.pyx
index 86b6533f5caf5..27402c8d255b6 100644
--- a/pandas/_libs/tslibs/period.pyx
+++ b/pandas/_libs/tslibs/period.pyx
@@ -861,6 +861,7 @@ cdef int64_t get_time_nanos(int freq, int64_t unix_date, int64_t ordinal) nogil:
     """
     cdef:
         int64_t sub, factor
+        int64_t nanos_in_day = 24 * 3600 * 10**9
 
     freq = get_freq_group(freq)
 
@@ -886,7 +887,7 @@ cdef int64_t get_time_nanos(int freq, int64_t unix_date, int64_t ordinal) nogil:
         # We must have freq == FR_HR
         factor = 10**9 * 3600
 
-    sub = ordinal - unix_date * 24 * 3600 * 10**9 / factor
+    sub = ordinal - unix_date * (nanos_in_day / factor)
     return sub * factor
 
 

From 405801aa963b1edc2079891c56b20b793d873618 Mon Sep 17 00:00:00 2001
From: nrebena <49879400+nrebena@users.noreply.github.com>
Date: Mon, 21 Sep 2020 22:36:53 +0200
Subject: [PATCH 2/3] TST: Test for Period over maximum timestamp

---
 pandas/tests/scalar/period/test_period.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pandas/tests/scalar/period/test_period.py b/pandas/tests/scalar/period/test_period.py
index dcef0615121c1..795021a260028 100644
--- a/pandas/tests/scalar/period/test_period.py
+++ b/pandas/tests/scalar/period/test_period.py
@@ -486,6 +486,13 @@ def test_period_cons_combined(self):
         with pytest.raises(ValueError, match=msg):
             Period("2011-01", freq="1D1W")
 
+    @pytest.mark.parametrize("hour", range(24))
+    def test_period_large_ordinal(self, hour):
+        # Issue #36430
+        # Integer overflow for Period over the maximum timestamp
+        p = pd.Period(ordinal=2562048 + hour, freq="1H")
+        assert p.hour == hour
+
 
 class TestPeriodMethods:
     def test_round_trip(self):

From f0e1e27ab1a73947cbfc59e5d0c4feed2055da55 Mon Sep 17 00:00:00 2001
From: nrebena <49879400+nrebena@users.noreply.github.com>
Date: Mon, 21 Sep 2020 23:40:13 +0200
Subject: [PATCH 3/3] TST: Add entry in whatsnew

---
 doc/source/whatsnew/v1.1.3.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v1.1.3.rst b/doc/source/whatsnew/v1.1.3.rst
index e3a96c69918db..e3b0f59c3edcc 100644
--- a/doc/source/whatsnew/v1.1.3.rst
+++ b/doc/source/whatsnew/v1.1.3.rst
@@ -36,6 +36,7 @@ Fixed regressions
 - Fixed regression in :meth:`read_excel` with ``engine="odf"`` caused ``UnboundLocalError`` in some cases where cells had nested child nodes (:issue:`36122`,:issue:`35802`)
 - Fixed regression in :class:`DataFrame` and :class:`Series` comparisons between numeric arrays and strings (:issue:`35700`,:issue:`36377`)
 - Fixed regression when setting empty :class:`DataFrame` column to a :class:`Series` in preserving name of index in frame (:issue:`36527`)
+- Fixed regression in :class:`Period` incorrect value for ordinal over the maximum timestamp (:issue:`36430`)
 
 .. ---------------------------------------------------------------------------