I accidentally entered incorrect bank account number for direct deposit. What do I do?

If you e-filed:

Banking information for direct deposit is wrong or closed

If you entered incorrect banking information for your refund, you can change it if your return is rejected.  If it is accepted, however, it is too late to change it.  The bank will reject the refund and send it back to the IRS.  Then the IRS will issue a paper check and mail it to the address you put on your tax return.  Expect a delay of at least a couple of weeks to receive your refund.

Here is what the IRS says about entering incorrect banking information

https://www.irs.gov/help-resources/tools-faqs/faqs-for-individuals/frequently-asked-tax-questions-answers/irs-procedures/refund-inquiries/refund-inquiries-18

If your refund is sent back to the IRS—- make certain that the address you entered on your Form 1040 is correct.  And…open all mail, even if it looks like junk mail.