diff --git a/cleantext/constants.py b/cleantext/constants.py
index 0c6c62e..74ae644 100644
--- a/cleantext/constants.py
+++ b/cleantext/constants.py
@@ -49,7 +49,7 @@
 )
 
 NUMBERS_REGEX = re.compile(
-    r"(?:^|(?<=[^\w,.]))[+–-]?(([1-9]\d{0,2}(,\d{3})+(\.\d*)?)|([1-9]\d{0,2}([ .]\d{3})+(,\d*)?)|(\d*?[.,]\d+)|\d+)(?:$|(?=\b))"
+    r"((?<=[a-zA-Z])\d+)|(\d+(?=[a-zA-Z]))|(?:^|(?<=[^\w,.]))[+–-]?(([1-9]\d{0,2}(,\d{3})+(\.\d*)?)|([1-9]\d{0,2}([ .]\d{3})+(,\d*)?)|(\d*?[.,]\d+)|\d+)(?:$|(?=\b))"
 )
 
 LINEBREAK_REGEX = re.compile(r"((\r\n)|[\n\v])+")
diff --git a/tests/test_clean.py b/tests/test_clean.py
index 71aaadf..d6cb757 100644
--- a/tests/test_clean.py
+++ b/tests/test_clean.py
@@ -93,8 +93,8 @@ def test_replace_phone_numbers():
 
 
 def test_replace_numbers():
-    text = "I owe $1,000.99 to 123 people for 2 +1 reasons."
-    proc_text = "I owe $*NUM* to *NUM* people for *NUM* *NUM* reasons."
+    text = "I owe $1,000.99 to 123 peo4ple for 2 +1 reasons."
+    proc_text = "I owe $*NUM* to *NUM* peo*NUM*ple for *NUM* *NUM* reasons."
     assert cleantext.replace_numbers(text, "*NUM*") == proc_text