Attempting to teleport to X/Z:30,000,000 doesn't work, despite message that indicates otherwise

I was messing around with the /tp command, and tried to go to 40,000,000 280 40,000,000, and it gave me an error saying it must be "at most" 30,000,000. So I typed

/tp @p 30000000 280 30000000

and got the same error:

The number you have entered (30000000.50) is too big, it must be at most 30000000

However, saying "at most 30000000" means that 30000000 is okay, but nothing over that. I entered 30000000 exactly, so it is "at most" 30000000, but I still got the error. In addition, it would be better if it didn't use scientific notation for big numbers here, as the numbers are never presented that way anywhere else in the game.