1980

Number
$1980$ (one thousand, nine hundred and eighty) is:
 * $2^2 \times 3^2 \times 5 \times 11$


 * The smallest term of the amicable triplet $\tuple {1980, 2016, 2556}$:
 * $\map {\sigma_1} {1980} = \map {\sigma_1} {2016} = \map {\sigma_1} {2556} = 6552 = 1980 + 2016 + 2556$


 * The $2$nd integer after $954$ whose digits are unchanged when subtracting its reversal:
 * $1980 - 0891 = 1089$

Also see