This number is a prime.
Wonder Book of Strange Facts (Ripley's Believe It or Not, Inc., 1957, p. 100) states that this (the 9th Mersenne prime) is the number of ways to make change for a five-dollar bill using pennies, nickels, dimes, quarters, half-dollar, and dollar coins. The correct answer is 98411, making this one of the largest prime errors ever found. [Rupinski]
Russian priest and mathematician Ivan Mikheevich Pervushin discovered in 1883 that Marin Mersenne's famous list was mistaken to exclude 261-1 = 2305843009213693951. It was known for a while as "Pervushin's number."