81642 has 16 divisors (see below), whose sum is σ = 178272. Its totient is φ = 24720.

The previous prime is 81637. The next prime is 81647. The reversal of 81642 is 24618.

It is an interprime number because it is at equal distance from previous prime (81637) and next prime (81647).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81642.

It is not an unprimeable number, because it can be changed into a prime (81647) by changing a digit.

81642 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 7 ways as a sum of consecutive naturals, for example, 553 + ... + 684.

It is an arithmetic number, because the mean of its divisors is an integer number (11142).

2⁸¹⁶⁴² is an apocalyptic number.

81642 is an abundant number, since it is smaller than the sum of its proper divisors (96630).

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 (89136).

81642 is a wasteful number, since it uses less digits than its factorization.

81642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1253.

The product of its digits is 384, while the sum is 21.

The square root of 81642 is about 285.7306423889. The cubic root of 81642 is about 43.3814980562.

It can be divided in two parts, 816 and 42, that added together give a palindrome (858).

The spelling of 81642 in words is "eighty-one thousand, six hundred forty-two".