Call the provider and ask. Though even the most difficult numbers become easy to remember after a while.

@NathanS What provider? You really need to provide better information

What provider are you with?

Here's Skinny's offer. I don't know if other providers offer this.

Does anyone ever remember mobile numbers anymore?  Thats what speed-dial is for!

Also try a service like https://www.internetmarketingninjas.com/seo-tools/phone-number-spell/  (from a google search) which will generate a mnemonic making the number easier to remember / dial.

You can usually pick number from the few in the office/shop.

I don't know any number apart from mine (did not change for 18 yrs) and police :(

I went down to Warehouse Stationery on a quiet day and took 20 minutes or so to look through a bin of hundreds of SIM cards until I found one that was really easy to remember.

Linux:

 

@NathanS What provider? You really need to provide better information

 

If it's 2degrees, customer care can change it for you over the phone. It's not in the self-care site anymore though.