diff --git a/django/forms/fields.py b/django/forms/fields.py
index 6d1c14586e..44bbfd8e6f 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -236,6 +236,7 @@ class IntegerField(Field):
     default_error_messages = {
         'invalid': _('Enter a whole number.'),
     }
+    re_decimal = re.compile(r'\.0*\s*$')
 
     def __init__(self, max_value=None, min_value=None, *args, **kwargs):
         self.max_value, self.min_value = max_value, min_value
@@ -259,8 +260,9 @@ class IntegerField(Field):
             return None
         if self.localize:
             value = formats.sanitize_separators(value)
+        # Strip trailing decimal and zeros.
         try:
-            value = int(str(value))
+            value = int(self.re_decimal.sub('', str(value)))
         except (ValueError, TypeError):
             raise ValidationError(self.error_messages['invalid'], code='invalid')
         return value
diff --git a/tests/forms_tests/tests/test_fields.py b/tests/forms_tests/tests/test_fields.py
index 477beee210..e70dc3c267 100644
--- a/tests/forms_tests/tests/test_fields.py
+++ b/tests/forms_tests/tests/test_fields.py
@@ -247,6 +247,23 @@ class FieldsTests(SimpleTestCase):
         f1 = IntegerField(localize=True)
         self.assertWidgetRendersTo(f1, '<input id="id_f" name="f" type="text" />')
 
+    def test_integerfield_float(self):
+        f = IntegerField()
+        self.assertEqual(1, f.clean(1.0))
+        self.assertEqual(1, f.clean('1.0'))
+        self.assertEqual(1, f.clean(b'1.0'))
+        self.assertEqual(1, f.clean(' 1.0 '))
+        self.assertEqual(1, f.clean('1.'))
+        self.assertEqual(1, f.clean(' 1. '))
+        self.assertRaisesMessage(ValidationError, "'Enter a whole number.'", f.clean, '1.5')
+        self.assertRaisesMessage(ValidationError, "'Enter a whole number.'", f.clean, '…')
+
+    def test_integerfield_big_num(self):
+        f = IntegerField()
+        self.assertEqual(9223372036854775808, f.clean(9223372036854775808))
+        self.assertEqual(9223372036854775808, f.clean('9223372036854775808'))
+        self.assertEqual(9223372036854775808, f.clean('9223372036854775808.0'))
+
     def test_integerfield_subclass(self):
         """
         Test that class-defined widget is not overwritten by __init__ (#22245).