17985 has 16 divisors (see below), whose sum is σ = 31680. Its totient is φ = 8640.

The previous prime is 17981. The next prime is 17987. The reversal of 17985 is 58971.

It is not a de Polignac number, because 17985 - 2² = 17981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111 + ... + 219.

It is an arithmetic number, because the mean of its divisors is an integer number (1980).

It is the magic constant of a 33 × 33 magic square.

2¹⁷⁹⁸⁵ is an apocalyptic number.

17985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

17985 is a deficient number, since it is larger than the sum of its proper divisors (13695).

17985 is a wasteful number, since it uses less digits than its factorization.

17985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128.

The product of its digits is 2520, while the sum is 30.

The square root of 17985 is about 134.1081652995. The cubic root of 17985 is about 26.2001320818.

Subtracting from 17985 its sum of digits (30), we obtain a triangular number (17955 = T₁₈₉).

The spelling of 17985 in words is "seventeen thousand, nine hundred eighty-five".