81870 has 16 divisors (see below), whose sum is σ = 196560. Its totient is φ = 21824.

The previous prime is 81869. The next prime is 81883. The reversal of 81870 is 7818.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81870.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81870.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1335 + ... + 1394.

It is an arithmetic number, because the mean of its divisors is an integer number (12285).

2⁸¹⁸⁷⁰ is an apocalyptic number.

81870 is an abundant number, since it is smaller than the sum of its proper divisors (114690).

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 (98280).

81870 is a wasteful number, since it uses less digits than its factorization.

81870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2739.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 81870 is about 286.1293413825. The cubic root of 81870 is about 43.4218440724.

It can be divided in two parts, 818 and 70, that added together give a palindrome (888).

The spelling of 81870 in words is "eighty-one thousand, eight hundred seventy".