District of Columbia gets 3 per the 23rd amendment
435 electors for Representatives from the 50 states, plus 100 for Senators from the 50 states, plus 3 for the District of Columbia. This adds up to 538, not 541.
DC was already counted.
Trump won 306 in 2016
Hill won 232
Notice total is 538
270 is magic number because it is one plus half (269)