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_2676980_4 (participating_parties VARCHAR, registered_voters VARCHAR)
### Question:
What is the number of participating parties when registered voters totaled 643629?
### Answer:
SELECT COUNT(participating_parties) FROM table_2676980_4 WHERE registered_voters = 643629