31985 has 4 divisors (see below), whose sum is σ = 38388. Its totient is φ = 25584.

The previous prime is 31981. The next prime is 31991. The reversal of 31985 is 58913.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4096 + 27889 = 64^2 + 167^2 .

It is a cyclic number.

It is not a de Polignac number, because 31985 - 2² = 31981 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31985.

It is not an unprimeable number, because it can be changed into a prime (31981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3194 + ... + 3203.

It is an arithmetic number, because the mean of its divisors is an integer number (9597).

2³¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

31985 is a deficient number, since it is larger than the sum of its proper divisors (6403).

31985 is an equidigital number, since it uses as much as digits as its factorization.

31985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6402.

The product of its digits is 1080, while the sum is 26.

The square root of 31985 is about 178.8435070110. The cubic root of 31985 is about 31.7430596358.

It can be divided in two parts, 319 and 85, that added together give a palindrome (404).

The spelling of 31985 in words is "thirty-one thousand, nine hundred eighty-five".