It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.
It is a cyclic number.
It is a Duffinian number.
It is a plaindrome in base 13 and base 16.
It is a congruent number.
231133 is an apocalyptic number.
It is an amenable number.
31133 is a wasteful number, since it uses less digits than its factorization.
31133 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 354.
The square root of 31133 is about 176.4454589951. The cubic root of 31133 is about 31.4586675500.
Adding to 31133 its reverse (33113), we get a palindrome (64246).
The spelling of 31133 in words is "thirty-one thousand, one hundred thirty-three".