It is a nialpdrome in base 10.
It is a congruent number.
It is an unprimeable number.
31100 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
231100 is an apocalyptic number.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
31100 is a wasteful number, since it uses less digits than its factorization.
31100 is an evil number, because the sum of its binary digits is even.
The square root of 31100 is about 176.3519208855. The cubic root of 31100 is about 31.4475485547.
Adding to 31100 its reverse (113), we get a palindrome (31213).
The spelling of 31100 in words is "thirty-one thousand, one hundred".