81431207280 is a `hidden beast` number, since 81 + 431 + 2 + 0 + 72 + 80 = 666.
It is a congruent number.
It is an unprimeable number.
Almost surely, 281431207280 is an apocalyptic number.
81431207280 is a gapful number since it is divisible by the number (80) 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 81431207280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144684221760).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
81431207280 is a wasteful number, since it uses less digits than its factorization.
81431207280 is an odious number, because the sum of its binary digits is odd.
The spelling of 81431207280 in words is "eighty-one billion, four hundred thirty-one million, two hundred seven thousand, two hundred eighty".