I actually use my Pythonista for also solving project Euler problems. I have PyCharm on the Mac laptop and the iCloud integration allows me to work on the same files on either the Mac or the iPhone. It works quite well but you have to be mindful of the availability of the libraries between the two platforms.
I’ve been impressed with the performance of Pythonista and it’s awesome that I can make use of a two hour bus commute using my iPhone.