Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_21146729_6 (series__number INTEGER, original_airdate VARCHAR)
### Question:
What was the series# with the original airdate of october 23, 1967?
### Answer:
SELECT MAX(series__number) FROM table_21146729_6 WHERE original_airdate = "October 23, 1967"