python判断给定的数是否是回文数

python判断给定的数是否是回文数此代码有很大的改进余地

#! /usr/bin/env python
#coding=utf-8
a = input()
b = str(a)
flag = True
for i in range(len(b)/2):
    if b[i]!=b[len(b)-i-1]:
        flag = False
        break
if flag:
    print "%d is huiwen number!" % a
else:
    print "%d is not huiwen number!" % a