Maybe the number is not 3 to 5 million illegals voting. Still, but the number IS substantial.

From The Washington Times:
Based on national polling by a consortium of universities, a report by Mr. Richman said 6.4 percent of the estimated 20 million adult noncitizens in the U.S. voted in November. He extrapolated that that percentage would have added 834,381 net votes for Mrs. Clinton, who received about 2.8 million more votes than Mr. Trump.

Mr. Richman calculated that Mrs. Clinton would have collected 81 percent of noncitizen votes.
“Is it plausible that non-citizen votes added to Clinton’s margin? Yes,” Mr. Richman wrote. “Is it plausible that non-citizen votes account for the entire nation-wide popular vote margin held by Clinton? Not at all.”