81822 has 16 divisors (see below), whose sum is σ = 176400. Its totient is φ = 25152.

The previous prime is 81817. The next prime is 81839. The reversal of 81822 is 22818.

It is a congruent number.

It is an unprimeable number.

81822 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, 447 + ... + 602.

It is an arithmetic number, because the mean of its divisors is an integer number (11025).

2⁸¹⁸²² is an apocalyptic number.

81822 is an abundant number, since it is smaller than the sum of its proper divisors (94578).

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 (88200).

81822 is a wasteful number, since it uses less digits than its factorization.

81822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067.

The product of its digits is 256, while the sum is 21.

The square root of 81822 is about 286.0454509339. The cubic root of 81822 is about 43.4133564050.

It can be divided in two parts, 81 and 822, that added together give a triangular number (903 = T₄₂).

The spelling of 81822 in words is "eighty-one thousand, eight hundred twenty-two".