I still remember my parent´s home landline from 30+ years ago (long gone) but I have no idea of what is my current one or any other of the many I have had to have over years due to telecoms´ bundles. They are not useful anymore, not even as a resilient second line since they are connected to the same fibre line. It is just a gimmick to extract a few more euros from the consumer.

Wow. This is Gold. I used to remember historical dates for school by adding/mixing with phone numbers. I had my "phone-diary" with a cryptic number pattern for each page (just in case, it got lost or stolen). I had my first personal (mobile) phone/number in 2000 and that was a fresh start.

Apropos. I can never remember my current phone number. Because it is never used. But they ask it anyway sometimes. So I have termux shortcut button to:

    termux-volume music 15
    while true; do
     termux-tts-speak -l fi 5 5 5 1 2 3 4 5
     sleep 1
    done

Works like a charm and all errors are at the receiving end.

I also remember quite many numbers of my friends from the elementary school. We lived in the same area so we had pretty similar numbers which made it easier to learn them - and to remember them after 25 years.