81830 has 24 divisors (see below), whose sum is σ = 172368. Its totient is φ = 27888.

The previous prime is 81817. The next prime is 81839. The reversal of 81830 is 3818.

It is a super-2 number, since 2×81830² = 13392297800, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81839) by changing a digit.

81830 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 407 + ... + 573.

It is an arithmetic number, because the mean of its divisors is an integer number (7182).

2⁸¹⁸³⁰ is an apocalyptic number.

81830 is an abundant number, since it is smaller than the sum of its proper divisors (90538).

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 (86184).

81830 is a wasteful number, since it uses less digits than its factorization.

81830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 81830 is about 286.0594343838. The cubic root of 81830 is about 43.4147712467.

Subtracting from 81830 its sum of digits (20), we obtain a triangular number (81810 = T₄₀₄).

It can be divided in two parts, 818 and 30, that added together give a palindrome (848).

The spelling of 81830 in words is "eighty-one thousand, eight hundred thirty".