FACTBOX: Facts about California's February 5 primary

(Reuters) - California is among 24 states taking part in "Super Tuesday," the February 5 contests in which voters will choose nominees from the Democratic and Republican parties for the November U.S. presidential election.

Following are a few facts about California and its primary, the biggest prize in terms of delegates:

* California is the most populous state, with more than 15 million registered voters, and has the eighth-largest economy in the world. Candidates have had to rely on advertising and news coverage, rather than the face-to-face "retail" politics they practiced in small states like New Hampshire and Iowa, in order to reach voters.

* A Reuters/C-SPAN/Zogby poll taken over the weekend shows Illinois Sen. Barack Obama leading rival New York Sen. Hillary Clinton 46 percent to 40 percent, with 9 percent undecided. Among Republicans, former Massachusetts Gov. Mitt Romney leads Arizona Sen. John McCain 40 percent to 37 percent, with 8 percent undecided.

* California sends 441 delegates to the Democratic National Convention, and 173 delegates on the Republican side, by far the most of any state voting on Super Tuesday. The majority of these delegates are allocated based on the winner in each of the state's 53 congressional districts.

* Polls close at 8 P.M. PST/0400 GMT Wednesday. Voters have been able to cast ballots by mail since January 7.

* Homeowners in the state have been hit hard by the subprime mortgage crisis. California ranks second in the nation for foreclosure filings, with inland cities like San Bernardino and Stockton especially hard hit.

* Median household income in the state is $54,385, well above the national median of $44,334. About 12.9 percent of the population lived below the poverty line, roughly in line with the national figure. The median age is 35.5, younger than the national average.

(Reporting by Dan Whitcomb and Andy Sullivan; Editing by Stacey Joyce)

Sources: National Association of Secretaries of State, RealtyTrac, U.S. Census Bureau, Almanac of American Politics, Real Clear Politics