While it is an M-type, its radar albedo is too low to allow a nickel-iron composition.

Klotho is similar to 21 Lutetia and 22 Kalliope in that all three are M-types of unknown composition.

It is named after Klotho or Clotho, one of the three Moirai, or Fates, in Greek mythology.

13-cm radar observations of this asteroid from the Arecibo Observatory between 1980 and 1985 were used to produce a diameter estimate of 108 km.

[7] In 1990, the asteroid was observed for four nights from the Collurania-Teramo Observatory in Italy, producing an asymmetric light curve that showed a rotation period of 10.927 ± 0.001 hours and a brightness variation of 0.17 ± 0.02 in magnitude.