***Perfect Bracket Odds:

There are 9,223,372,036,854,775,808 possible brackets (9.2 quintillion)
That's the number nine followed by eighteen zeros!
That’s ONE MILLION times bigger than 9 TRILLION!

Some examples of just how big this number is:

If everyone on the planet each randomly filled out a bracket, the odds would be over ONE BILLION to 1 against any person having a perfect bracket.

If one bracket per second was filled out, it would take 292 BILLION years to fill out all possible brackets (that's 20 times longer than the universe has existed).

If all the people on earth filled out one bracket per second, it would take over 42 years to fill out every possible bracket.

All possible brackets on normal paper would circle the globe over 21 MILLION TIMES.

All possible brackets (on standard paper) would weigh over 184 TRILLION TONS (that’s over 500 MILLION times more than the Empire State Building weighs)

68 vs. 64 teams:
The calculations above assume a 64 team bracket – if expanded to consider 68 teams, multiple the figures by 4.