Hello,
Id like delete my account with the ID 534257
how can I delete it?

You can\'t.
Just stop using it.

1) In the Projects tab, click on this projects name, then click the No new tasks button.
2) In the Tasks tab, click on the model\'s name, then click the Abort button.
3) Once the model has disappeared, go back to the Projects tab, and click the Detach button.