31993 has 8 divisors (see below), whose sum is σ = 36288.
Its totient is φ = 27984.
The previous prime is 31991. The next prime is 32003. The reversal of 31993 is 39913.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is not a de Polignac number, because 31993 - 21 = 31991 is a prime.
It is an Ulam number.
It is a Duffinian number.
It is a nialpdrome in base 14.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (31991) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246 + ... + 352.
It is an arithmetic number, because the mean of its divisors is an integer number (4536).
231993 is an apocalyptic number.
It is an amenable number.
31993 is a deficient number, since it is larger than the sum of its proper divisors (4295).
31993 is a wasteful number, since it uses less digits than its factorization.
31993 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 143.
The product of its digits is 729, while the sum is 25.
The square root of 31993 is about 178.8658715351.
The cubic root of 31993 is about 31.7457059107.
It can be divided in two parts, 31 and 993, that added together give a 10-th power (1024 = 210).
The spelling of 31993 in words is "thirty-one thousand, nine hundred ninety-three".