181985 has 8 divisors (see below), whose sum is σ = 231336. Its totient is φ = 136960.

The previous prime is 181981. The next prime is 181997. The reversal of 181985 is 589181.

181985 = T₈₆ + T₈₇ + ... + T₁₁₉.

181985 = 56² + 57² + ... + 89².

It is a happy number.

181985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 85264 + 96721 = 292^2 + 311^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 181985 - 2² = 181981 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 181985.

It is not an unprimeable number, because it can be changed into a prime (181981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 986 + ... + 1155.

It is an arithmetic number, because the mean of its divisors is an integer number (28917).

2¹⁸¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

181985 is a deficient number, since it is larger than the sum of its proper divisors (49351).

181985 is a wasteful number, since it uses less digits than its factorization.

181985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2163.

The product of its digits is 2880, while the sum is 32.

The square root of 181985 is about 426.5969995206. The cubic root of 181985 is about 56.6689541560.

The spelling of 181985 in words is "one hundred eighty-one thousand, nine hundred eighty-five".