If you ever wrote a check to anyone, your routing number is on the check (it's that long number after your account number). Anyone who gets your check has your routing number & can deposit into your account. That's how I get my SS. That's probably how the IRS deposited my stimulus payment into my account.We got our earlier checks by mail, but this one came Direct Deposit....I'm still trying to figure out how the IRS got our bank account number, as I always get our tax refunds via the mail. I guess this is another example of "Big Brother" knowing everything about us.