In Powerball under the 5/59 + 1/35 · Jan 2012 – Oct 2015 rules — 388 draws, 5 from 1–59 (an earlier era).
24times drawn · chance expected 33 −1.62σ
1draws waiting · a wait this long: >99% for any number
15.3average wait between appearances · chance says 11.8
52longest completed wait · 22% chance of one at least that long
21 is drawn as often as chance explains
Drawn 24 times in 388 draws against 32.9 expected, −1.62σ. Each draw is independent: after 1 draws away it is exactly as likely tonight as a number drawn yesterday.
21
Number 21, draw by draw
Drawn 24 times in 388 draws · average wait 15.3 draws · longest completed wait 52 · waiting 1 draws now
a completed wait — darker is longer the wait still running — a lower bound, not a finished gap
Where it lands in a sorted draw
Sort a draw and 21 has a favourite seat — chance gives a small number the low positions more often. That is the shape of sorting, not of the machine.
Never drawn alongside 5 of the other 58 numbers; chance expects about 11 such strangers by now. Every pair →
How many people play it
Under the crowd model, 21 is picked about 1.04× as often as an indifferent choice — 14th most popular of 59. That changes nothing about whether it comes up, and everything about how many ways a jackpot on it would be shared.
Nothing here predicts the next draw. A number’s history is a record of a fair machine’s past, and the machine keeps none of it: 21 is drawn with probability 5/59 tonight whatever it did last week.