There is a theoretical possibility to enter a number (masochists only) using Yes/No questions and binary search:
Is the number >100? No
Is the number >50? Yes
Is the number >75? No
Is the number >62? No
Is the number >56? …
Yes, you can use a webhook as a way to input the numbers into the flow.
I have this working with the following: Tasker on Android phone and the Tasker plugins Join, Auto Notification and (optional) AutoTools.
Homey and Join communicate via webhooks with each other and sent over the data. Auto Notification takes care of the pop-up on the phone and with AutoTools you have some more options in the pop-up.
Yes these are paid apps and the setup is not plug 'n play, but it gives you a lot of options for user input from your phone into your Homey flows.