Source: here.
The most glorious urvashI is invoked by her mahAmantra:
oM hrIM eM | abhi na iLA yUthasya mAtA sman nadIbhir urvashI vA
gR^iNAtu | oM hrIM eM | urvashI vA bR^ihad-divA gR^iNAnA .abhyUrNvAnA
prabhR^ithasyAyoH | huM svAhA
The mantras of urvashI and tillotamA are unparalled in the bliss they
give. The highest joys of svarga may be glimpsed by the invocation of
the glorious apsaras of great power. The might of the pa~nchachoDA of
the apsaras protects him from his bhrAtR^ivyas.
The mighty saubhAgya sarasvatI formula brings her to the votary for
saubhAgya:
oM aiM | sA naH sudAnur mR^iLayantI devI prati dravantI suvitAya gamyAH
| aiM svAhA