To add a little context, here, America's relative poverty at that time cannot be overlooked. A person who had X dollars-adjusted during 1776 is in a much different place in 1860 with the same X dollars-adjusted and in a much different place in 1960 with the same X dollars-adjusted. Comparatively, one gets 'poorer' the closer you get to today even if the value never changes because everyone else is getting richer. In 1776 being more than a subsistence farmer puts you in a pretty position.

NBER has a good paper on this. As I understand it, then, not only is Washington worth in inflation-adjusted dollars 500 million, making him the richest president (more than even Mitt Romeny, if he had been elected) and by far richer than the vast majority of Congressional Representatives it would also make him, at the time, comparatively, 'richer' than similarly situated 525 millionaires today. His wealth at the time would place him squarely in the top .01% of then-America.