8128
1105 various sums of two squares 2520 1st highly composite number 4225 various sums of two squares 5525 various sums of two squares 5777 first of two 'Stern numbers' 5993 second of the Stern numbers 6174 Kaprekar's constant 4-digit 8125 various sums of two squares 8128 ⇐ only 4-digit perfect number collected by artmetic monoalgorithmic digital art horn_torus real world ↔ complex numbers ⌂© |