diff --git a/frouros/utils/stats.py b/frouros/utils/stats.py
index f7e80aa..58f6756 100644
--- a/frouros/utils/stats.py
+++ b/frouros/utils/stats.py
@@ -2,6 +2,7 @@
 
 import abc
 import itertools
+import math
 from functools import partial
 from multiprocessing import Pool
 from typing import Any, Callable, Optional, Tuple, Union
@@ -248,7 +249,7 @@ def permutation(  # pylint: disable=too-many-arguments,too-many-locals
     X_num_samples, Y_num_samples = X.shape[0], Y.shape[0]  # noqa: N806
     data = np.concatenate([X, Y])
 
-    max_num_permutations = np.math.factorial(data.shape[0])
+    max_num_permutations = math.factorial(data.shape[0])
     if num_permutations >= max_num_permutations:
         logger.warning(
             "Number of permutations (%s) is greater or equal "
diff --git a/pyproject.toml b/pyproject.toml
index 8df9f01..2cf6532 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,7 +37,7 @@ classifiers = [
 requires-python = ">=3.9,<3.13"
 dependencies = [
     "matplotlib>=3.8.2,<3.10",
-    "numpy>=1.26.3,<1.27",
+    "numpy>=1.26.3,<2.1",
     "requests>=2.31.0,<2.33",
     "scipy>=1.12.0,<1.14",
     "tqdm>=4.66.1,<5.0",