Why must the speed of light be 186,282 mi/s?

Why can't it be some other value, like 586,282 mi/s? I've read that the speed of light in a vacuum (and its constancy) is a prediction of Maxwell's equations, but I've been unable to discover why exactly c has the value that it does. Is it a complicated equation that I'd be unable to understand without years of mathematical training? Or can anyone explain it to me in layman's terms, or point to a website that explains it for a non-scientist?