For how many consecutive numbers Collatz conjecture was checked? I heard here that Collatz conjecture was checked at least for every first $5 \cdot 10^{18}$ natural numbers, but I cannot find any source or actual information about this. Can anyone help to find out up to which number (or factor of 10) we can now say that Collatz Conjecture is definitely true?

I think that is a few orders of magnitude too low. According to this discussion board, the number is at least $2 \cdot 10^{21}$.
