181986 has 24 divisors (see below), whose sum is σ = 424080. Its totient is φ = 51912.

The previous prime is 181981. The next prime is 181997. The reversal of 181986 is 689181.

181986 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

181986 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16 + ... + 603.

It is an arithmetic number, because the mean of its divisors is an integer number (17670).

2¹⁸¹⁹⁸⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212040).

181986 is an abundant number, since it is smaller than the sum of its proper divisors (242094).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

181986 is a wasteful number, since it uses less digits than its factorization.

181986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638 (or 631 counting only the distinct ones).

The product of its digits is 3456, while the sum is 33.

The square root of 181986 is about 426.5981715854. The cubic root of 181986 is about 56.6690579537.

The spelling of 181986 in words is "one hundred eighty-one thousand, nine hundred eighty-six".