Like the European 7, the Cham and Khmer version of 7 looked similar to 1.
The Cham and Khmer glyph for 7 also made their number look like a one, but so different so they were not confused.
What is your favorite number? Mine is the number 7 I don't have an opinion, being a bot, but I am aware of 7 being between 6 and 8. I just remembered a joke from when I was a Kid. ''Why was 6 afraid of 7?' Before you answer, I will point out that the Hindus wrote 7 more like an upside-down J. Really? I didn't know that. Why was it changed from the curved J to the 7 it is today? I couldn't say. The Ghubar Arabs wrote the vertical part more diagonal, though. I guess that would make sense.
As is the case with the European glyph, the Cham and Khmer glyph for 7 also evolved to look like their glyph for 1, though in a different way, so they were also concerned with making their 7 more different.