81858 has 16 divisors (see below), whose sum is σ = 187200. Its totient is φ = 23376.

The previous prime is 81853. The next prime is 81869. The reversal of 81858 is 85818.

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

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81858.

It is not an unprimeable number, because it can be changed into a prime (81853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 933 + ... + 1016.

It is an arithmetic number, because the mean of its divisors is an integer number (11700).

2⁸¹⁸⁵⁸ is an apocalyptic number.

81858 is an abundant number, since it is smaller than the sum of its proper divisors (105342).

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 (93600).

81858 is a wasteful number, since it uses less digits than its factorization.

81858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1961.

The product of its digits is 2560, while the sum is 30.

The square root of 81858 is about 286.1083710764. The cubic root of 81858 is about 43.4197224666.

It can be divided in two parts, 81 and 858, that added together give a palindrome (939).

The spelling of 81858 in words is "eighty-one thousand, eight hundred fifty-eight".