diff --git a/frappe/utils/__init__.py b/frappe/utils/__init__.py
index 7cb5decb3b..c1362bb33b 100644
--- a/frappe/utils/__init__.py
+++ b/frappe/utils/__init__.py
@@ -142,6 +142,9 @@ def validate_phone_number(phone_number, throw=False):
 	if not phone_number:
 		return False
 
+	if not isinstance(phone_number, str):
+		phone_number = str(phone_number)
+
 	phone_number = phone_number.strip()
 	match = PHONE_NUMBER_PATTERN.match(phone_number)