diff --git a/src/corelib/serialization/qtextstream.cpp b/src/corelib/serialization/qtextstream.cpp
index 2b6aed5d21c..372091a9d7f 100644
--- a/src/corelib/serialization/qtextstream.cpp
+++ b/src/corelib/serialization/qtextstream.cpp
@@ -2204,44 +2204,34 @@ QTextStream &QTextStream::operator>>(char *c)
  */
 void QTextStreamPrivate::putNumber(qulonglong number, bool negative)
 {
-    QString result;
-
     unsigned flags = 0;
     const QTextStream::NumberFlags numberFlags = params.numberFlags;
     if (numberFlags & QTextStream::ShowBase)
         flags |= QLocaleData::ShowBase;
-    if (numberFlags & QTextStream::ForceSign)
+    // ForceSign is irrelevant when we'll be including a sign in any case:
+    if ((numberFlags & QTextStream::ForceSign) && !negative)
         flags |= QLocaleData::AlwaysShowSign;
     if (numberFlags & QTextStream::UppercaseBase)
         flags |= QLocaleData::UppercaseBase;
     if (numberFlags & QTextStream::UppercaseDigits)
         flags |= QLocaleData::CapitalEorX;
 
-    // add thousands group separators. For backward compatibility we
-    // don't add a group separator for C locale.
+    // Group digits. For backward compatibility, we skip this for the C locale.
     if (locale != QLocale::c() && !locale.numberOptions().testFlag(QLocale::OmitGroupSeparator))
         flags |= QLocaleData::GroupDigits;
 
     const QLocaleData *dd = locale.d->m_data;
     int base = params.integerBase ? params.integerBase : 10;
-    if (negative && base == 10) {
-        result = dd->longLongToString(-static_cast<qlonglong>(number), -1,
-                                      base, -1, flags);
-    } else if (negative) {
-        // Workaround for backward compatibility for writing negative
-        // numbers in octal and hex:
-        // QTextStream(result) << Qt::showbase << Qt::hex << -1 << oct << -1
-        // should output: -0x1 -0b1
-        result = dd->unsLongLongToString(number, -1, base, -1, flags);
+    QString result = dd->unsLongLongToString(number, -1, base, -1, flags);
+    if (negative) {
         result.prepend(locale.negativeSign());
-    } else {
-        result = dd->unsLongLongToString(number, -1, base, -1, flags);
-        // workaround for backward compatibility - in octal form with
-        // ShowBase flag set zero should be written as '00'
-        if (number == 0 && base == 8 && params.numberFlags & QTextStream::ShowBase
-            && result == "0"_L1) {
-            result.prepend(u'0');
-        }
+    } else if (number == 0 && base == 8 && params.numberFlags & QTextStream::ShowBase
+               && result == "0"_L1) {
+        // Workaround for backward compatibility - in octal form with ShowBase
+        // flag set, zero should get its 0 prefix before its 0 value, but
+        // QLocalePrivate only adds the prefix if the number doesn't start with
+        // a zero.
+        result.prepend(u'0');
     }
     putString(result, true);
 }
diff --git a/tests/auto/corelib/serialization/qtextstream/tst_qtextstream.cpp b/tests/auto/corelib/serialization/qtextstream/tst_qtextstream.cpp
index d66cc21e318..37aeb3f1d47 100644
--- a/tests/auto/corelib/serialization/qtextstream/tst_qtextstream.cpp
+++ b/tests/auto/corelib/serialization/qtextstream/tst_qtextstream.cpp
@@ -1123,6 +1123,7 @@ void tst_QTextStream::octTest_data()
     QTest::addColumn<QByteArray>("data");
 
     QTest::newRow("0") << 0 << QByteArray("00");
+    QTest::newRow("40") << 40 << QByteArray("050");
 }
 
 // ------------------------------------------------------------------------------
@@ -2716,7 +2717,6 @@ void tst_QTextStream::manipulators()
     stream << textData;
     stream.flush();
 
-    QEXPECT_FAIL("hex-negative", "Discovered while fixing QTBUG-133269", Continue);
     QCOMPARE(buffer.data(), result);
 }