It is a self number, because there is not a number n which added to its sum of digits gives 31540.
It is a congruent number.
31540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
231540 is an apocalyptic number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 31540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35280).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
31540 is a wasteful number, since it uses less digits than its factorization.
31540 is an odious number, because the sum of its binary digits is odd.
The square root of 31540 is about 177.5950449759. The cubic root of 31540 is about 31.5951602907.
The spelling of 31540 in words is "thirty-one thousand, five hundred forty".