diff --git a/pytools/persistent_dict.py b/pytools/persistent_dict.py
index 14eda873..96101f6e 100644
--- a/pytools/persistent_dict.py
+++ b/pytools/persistent_dict.py
@@ -163,12 +163,6 @@ class KeyBuilder:
         may stop working as early as 2022.
 
         .. versionadded:: 2021.2
-
-    .. note::
-
-        Some key-building uses system byte order, so the built keys may not match
-        across different systems. It would be desirable to fix this, but this is
-        not yet done.
     """
 
     # this exists so that we can (conceivably) switch algorithms at some point
@@ -274,16 +268,7 @@ def update_for_type(self, key_hash: Hash, key: type) -> None:
     update_for_ABCMeta = update_for_type
 
     def update_for_int(self, key_hash: Hash, key: int) -> None:
-        sz = 8
-        while True:
-            try:
-                # Must match system byte order so that numpy and this
-                # generate the same string of bytes.
-                # https://github.com/inducer/pytools/issues/259
-                key_hash.update(key.to_bytes(sz, byteorder=sys.byteorder, signed=True))
-                return
-            except OverflowError:
-                sz *= 2
+        key_hash.update(str(key).encode("utf-8"))
 
     def update_for_enum(self, key_hash: Hash, key: Enum) -> None:
         self.update_for_str(key_hash, str(key))
diff --git a/pytools/test/test_persistent_dict.py b/pytools/test/test_persistent_dict.py
index b6dec54f..0b5cb29a 100644
--- a/pytools/test/test_persistent_dict.py
+++ b/pytools/test/test_persistent_dict.py
@@ -461,9 +461,16 @@ def test_scalar_hashing() -> None:
     assert keyb(np.int32(1)) == keyb(np.int32(1))
     assert keyb(np.int32(2)) != keyb(np.int32(1))
     assert keyb(np.int64(1)) == keyb(np.int64(1))
-    assert keyb(1) == keyb(np.int64(1))
+    assert keyb(1) != keyb(np.int64(1))
     assert keyb(1) != keyb(np.int32(1))
 
+    assert keyb(1) == keyb("1")
+    assert keyb(1.0) != keyb("1.0")  # '1.0' uses hex representation
+    assert keyb(1+1j) == keyb("(1+1j)")
+
+    assert keyb(np.float64(1.0)) != keyb(1.0)
+    assert keyb(np.complex128(1.0+2.0j)) != keyb(1.0+2.0j)
+
     assert keyb(np.longlong(1)) == keyb(np.longlong(1))
 
     assert keyb(np.float16(1.1)) == keyb(np.float16(1.1))
@@ -595,7 +602,7 @@ class MyDC:
         name: str
         value: int
 
-    assert keyb(MyDC("hi", 1)) == "d1a1079f1c10aa4f"
+    assert keyb(MyDC("hi", 1)) == "72c25f5d0ac2bda7"
 
     assert keyb(MyDC("hi", 1)) == keyb(MyDC("hi", 1))
     assert keyb(MyDC("hi", 1)) != keyb(MyDC("hi", 2))
@@ -619,7 +626,7 @@ class MyAttrs:
         name: str
         value: int
 
-    assert (keyb(MyAttrs("hi", 1)) == "5b6c5da60eb2bd0f")  # type: ignore[call-arg]
+    assert (keyb(MyAttrs("hi", 1)) == "6e8bfc4394f82985")  # type: ignore[call-arg]
 
     assert keyb(MyAttrs("hi", 1)) == keyb(MyAttrs("hi", 1))  # type: ignore[call-arg]
     assert keyb(MyAttrs("hi", 1)) != keyb(MyAttrs("hi", 2))  # type: ignore[call-arg]