CRLNumber needs to be a class for reasons.
diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index 45c0df5..7e89ac6 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -182,7 +182,7 @@
 def _decode_crl_number(backend, ext):
     asn1_int = backend._ffi.cast("ASN1_INTEGER *", ext)
     asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
-    return backend._asn1_integer_to_int(asn1_int)
+    return x509.CRLNumber(backend._asn1_integer_to_int(asn1_int))
 
 
 class _X509ExtensionParser(object):
diff --git a/src/cryptography/x509/__init__.py b/src/cryptography/x509/__init__.py
index 70e1d3d..c4434fd 100644
--- a/src/cryptography/x509/__init__.py
+++ b/src/cryptography/x509/__init__.py
@@ -14,7 +14,7 @@
 from cryptography.x509.extensions import (
     AccessDescription, AuthorityInformationAccess,
     AuthorityKeyIdentifier, BasicConstraints, CRLDistributionPoints,
-    CertificatePolicies, DistributionPoint, DuplicateExtension,
+    CRLNumber, CertificatePolicies, DistributionPoint, DuplicateExtension,
     ExtendedKeyUsage, Extension, ExtensionNotFound, ExtensionType, Extensions,
     GeneralNames, InhibitAnyPolicy, IssuerAlternativeName, KeyUsage,
     NameConstraints, NoticeReference, OCSPNoCheck, PolicyInformation,
@@ -124,6 +124,7 @@
     "ExtendedKeyUsage",
     "OCSPNoCheck",
     "BasicConstraints",
+    "CRLNumber",
     "KeyUsage",
     "AuthorityInformationAccess",
     "AccessDescription",
diff --git a/src/cryptography/x509/extensions.py b/src/cryptography/x509/extensions.py
index 71ce8a1..15feb71 100644
--- a/src/cryptography/x509/extensions.py
+++ b/src/cryptography/x509/extensions.py
@@ -109,6 +109,31 @@
 
 
 @utils.register_interface(ExtensionType)
+class CRLNumber(object):
+    oid = ExtensionOID.CRL_NUMBER
+
+    def __init__(self, crl_number):
+        if not isinstance(crl_number, six.integer_types):
+            raise TypeError("crl_number must be an integer")
+
+        self._crl_number = crl_number
+
+    def __eq__(self, other):
+        if not isinstance(other, CRLNumber):
+            return NotImplemented
+
+        return self.crl_number == other.crl_number
+
+    def __ne__(self, other):
+        return not self == other
+
+    def __repr__(self):
+        return "<CRLNumber({0})>".format(self.crl_number)
+
+    crl_number = utils.read_only_property("_crl_number")
+
+
+@utils.register_interface(ExtensionType)
 class AuthorityKeyIdentifier(object):
     oid = ExtensionOID.AUTHORITY_KEY_IDENTIFIER