Almost the only place where you see large sums of money written out in full is in spam emails. If I’m reading a budget document at work, a figure like £150,000 is written as £150k, and £28,000,000 is written as £28 million; or else, these are in tables with a footnote like “all figures in thousands”. I’ve just realised that this is one of the mental heuristics I use to determine whether something is spam or not—the moment I see a long string of zeroes with a currency symbol prefixed, a little “spam” flag goes off in my head.