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Australian visas are completely electronic and are linked to your passport number. The passport number is the number appearing on the second line in the machine readable zone of your passport, as highlighted in the image below.
If the passport number shown in your visa grant letter does not match the one in your passport, then there would be an issue. Airlines check your visas electronically against Australian government systems using your passport details. At the very least you will experience delays when checking in, as the check-in system will not be able to find the visa record. At worst you will be denied boarding.
The Department's website contains instructions on updating the passport number.