It is a congruent number.
It is an unprimeable number.
Almost surely, 220731228 is an apocalyptic number.
20731228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 20731228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22226400).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
20731228 is a wasteful number, since it uses less digits than its factorization.
20731228 is an odious number, because the sum of its binary digits is odd.
The square root of 20731228 is about 4553.1558286534. The cubic root of 20731228 is about 274.7103418414.
The spelling of 20731228 in words is "twenty million, seven hundred thirty-one thousand, two hundred twenty-eight".