Just for information, 1 light-year is equivalent to the distance travelled by light in 1 year moving in a vacuum. 1 light-year is about 9.4607 * 10^{15} metres.

1 astronomical unit (AU) is equivalent to the average radius of the Earth's orbit. 1 AU is about 1.4960 * 10^{11} metres.

Simple arithmetic calculation yields the answer that 1 light-year = 63240 AU to a good approximation.
Answered by:
Ryan Leong, Undergraduate, NUS, Singapore

'The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.'