The SI prefix "mega" represents a factor of
10^{6}, or in exponential notation, 1E6.

So 1 megaparsec = 10^{6} parsecs.

The definition of a parsec is as follows:

The parsec (symbol pc) is a unit of length used in astronomy. It stands for "parallax of one arc second", and is approximately 19,131,554,073,600 (19 trillion) miles.

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