81860 has 12 divisors (see below), whose sum is σ = 171948. Its totient is φ = 32736.

The previous prime is 81853. The next prime is 81869. The reversal of 81860 is 6818.

It can be written as a sum of positive squares in 2 ways, for example, as 31684 + 50176 = 178^2 + 224^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2027 + ... + 2066.

It is an arithmetic number, because the mean of its divisors is an integer number (14329).

2⁸¹⁸⁶⁰ is an apocalyptic number.

It is an amenable number.

81860 is an abundant number, since it is smaller than the sum of its proper divisors (90088).

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 (85974).

81860 is a wasteful number, since it uses less digits than its factorization.

81860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4102 (or 4100 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 81860 is about 286.1118662342. Note that the first 3 decimals coincide. The cubic root of 81860 is about 43.4200760820.

It can be divided in two parts, 818 and 60, that added together give a palindrome (878).

The spelling of 81860 in words is "eighty-one thousand, eight hundred sixty".