The Powerball jackpot has rolled up to $478 million in advance of Saturday night’s drawing. The grand prize, which has an estimated lump-sum cash value of $330.6 million, is the largest since the record-breaking $1.6 billion draw in January and the fifth-largest in Powerball history. It comes after a run of 23 draws without a winner that began May 11. Since Wednesday’s drawing, the Colorado lottery has sold just less than $1 million in Powerball tickets, according to spokeswoman Kelly Tabor. Saturday, “it’s quite possible we could even double that, as many players, especially ‘jackpot chasers’ like to jump in at the last minute,” Tabor said in an e-mail. To put that in context, a more typical (i.e., smaller jackpot) Powerball drawing brings in about $400,000 in sales, she said. But — back to the prize money — just how much is $330.6 million? It’s nearly equal making $159,000 an hour, 40 hours a week, for an entire year. It’s enough to buy Mike Shanahan’s $22 million mansion 15 times over. It’s more than three times the net worth of the Colorado Rapids.