  We investigate the photometric properties of six super stellar clusters
(SSCs) seen in both the optical and near-infrared Hubble Space Telescope images
of the local ultraluminous starburst galaxy Arp 220. Three of the SSCs are
located in the central 0.5 kpc region. The remaining three are in the
circumnuclear region between 0.5 kpc and 2.5 kpc from the centre. Comparing the
observed spectral energy distributions (SEDs) of the SSCs with the Starburst99
models of Leitherer et al., we confirm that all the three nuclear SSCs are
heavily obscured ($A_V \sim 10$ mag). Considering the results from this
comparison in conjunction with measurements of the near-infrared CO absorption
index and of millimetre CO line widths and luminosities, we estimate the ages
of the nuclear SSCs to be $10^7 - 10^8$ yrs. The bolometric luminosity of the
three nuclear SSCs is at most one-fifth of the total bolometric luminosity of
Arp 220. On the other hand, the circumnuclear SSCs have little internal
extinction ($A_V \leq$ 1 mag). These contribute negligibly to the total
bolometric luminosity.
