CREATE TABLE table_5140 ("County" TEXT, "Per capita income" TEXT, "Median household income" TEXT, "Median family income" TEXT, "Population" FLOAT, "Number of households" FLOAT)

What is the largest number of households with median family income of $52,106 with less than 21,403 in population?
SELECT MAX("Number of households") FROM table_5140 WHERE "Median family income" = '$52,106' AND "Population" < '21,403'
SELECT MAX("Number of households") FROM "table_5140" WHERE "Median family income" = '$52,106' AND "Population" < '21,403'