Hundreds of millions of people around the world are using this app.
Tips
grammar
几 (jǐ) means 'several' or 'how many'. 亿 (yì) is 100 million. So 几亿 = 'several hundred million.' Chinese numbers scale in units of 万 (10,000) and 亿 (100,000,000), which can be confusing when converting to English billions.