At Apple’s annual meeting in Cupertino, California, chief executive Tim Cook dropped a curious factoid: In the past 16 months, Apple has bought 23 companies. Like Cisco, IBM, Salesforce.com, Oracle, Yahoo, and other aging tech giants seeking to stay relevant, Apple has been on an acquisition binge. The mobile device, PC, and software maker keeps lots of cash on hand. Enough cash to round up a whole flock of acqui-hires, technology buys, and other M&A deals.