Answer
$(1.55780644887275*10^{-3})*1000000=1557.80644887275s$
Work Step by Step
Pulsar revolution means one million rotations.
Number of rotation=rate*time.
Rate is 1 rotation over (1.55780644887275*10$^{-3}$)s.
To cancel out the unit of rotation, use multiplication, as (1.55780644887275*10$^{-3}$)s over 1 rotation.
