5020

Number
$5020$ (five thousand and twenty) is:
 * $2^2 \times 5 \times 251$


 * The smaller of the $4$th amicable pair, with $5564$:
 * $\sigma \left({5020}\right) = \sigma \left({5564}\right) = 10 \, 584 = 5020 + 5564$