81842 has 8 divisors (see below), whose sum is σ = 124032. Its totient is φ = 40500.

The previous prime is 81839. The next prime is 81847. The reversal of 81842 is 24818.

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

It is a super-2 number, since 2×81842² = 13396225928, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81847) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 167 + ... + 437.

It is an arithmetic number, because the mean of its divisors is an integer number (15504).

2⁸¹⁸⁴² is an apocalyptic number.

81842 is a deficient number, since it is larger than the sum of its proper divisors (42190).

81842 is a wasteful number, since it uses less digits than its factorization.

81842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424.

The product of its digits is 512, while the sum is 23.

The square root of 81842 is about 286.0804082771. The cubic root of 81842 is about 43.4168933364.

The spelling of 81842 in words is "eighty-one thousand, eight hundred forty-two".