This looks look epoch timestamps which is number of seconds since 1st January
1970 :
In [71]:pd.to_datetime(df['date'], unit='s')Out[71]:0 2016-10-13 03:32:091 2016-10-13 03:32:102 2016-10-13 03:36:433 2016-10-13 03:36:454 2016-10-13 03:36:455 2016-10-13 03:36:45Name: date, dtype: datetime64[ns]
