81786 has 16 divisors (see below), whose sum is σ = 167904. Its totient is φ = 26544.

The previous prime is 81773. The next prime is 81799. The reversal of 81786 is 68718.

It is an interprime number because it is at equal distance from previous prime (81773) and next prime (81799).

It is an Ulam number.

It is a Curzon number.

It is an unprimeable number.

81786 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 7 ways as a sum of consecutive naturals, for example, 100 + ... + 416.

It is an arithmetic number, because the mean of its divisors is an integer number (10494).

2⁸¹⁷⁸⁶ is an apocalyptic number.

81786 is a gapful number since it is divisible by the number (86) formed by its first and last digit.

81786 is an abundant number, since it is smaller than the sum of its proper divisors (86118).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83952).

81786 is a wasteful number, since it uses less digits than its factorization.

81786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365.

The product of its digits is 2688, while the sum is 30.

The square root of 81786 is about 285.9825169482. The cubic root of 81786 is about 43.4069884759.

It can be divided in two parts, 817 and 86, that added together give a triangular number (903 = T₄₂).

The spelling of 81786 in words is "eighty-one thousand, seven hundred eighty-six".