diff --git a/imp/extern/__init__.py b/imp/extern/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/imp/math/primefac.py b/imp/extern/primefac.py
similarity index 100%
rename from imp/math/primefac.py
rename to imp/extern/primefac.py
diff --git a/imp/math/numbers/__init__.py b/imp/math/numbers/__init__.py
index f4193b8..22a0d21 100644
--- a/imp/math/numbers/__init__.py
+++ b/imp/math/numbers/__init__.py
@@ -6,7 +6,7 @@ Terminology:
     the "prime proper divisors of n". 
 '''
 
-from imp.math.primefac import primefac
+from imp.extern.primefac import primefac
 
 def factors(n: int) -> int:
     pfactors: list[tuple[int, int]] = []
diff --git a/imp/math/numbers/functions.py b/imp/math/numbers/functions.py
index 6cafa7f..8addd51 100644
--- a/imp/math/numbers/functions.py
+++ b/imp/math/numbers/functions.py
@@ -1,5 +1,3 @@
 def factorial(n: int) -> int:
     if n == 0: return 1
     return n * factorial(n-1)
-
-def