81871 has 8 divisors (see below), whose sum is σ = 89600. Its totient is φ = 74520.

The previous prime is 81869. The next prime is 81883. The reversal of 81871 is 17818.

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

It is a cyclic number.

It is not a de Polignac number, because 81871 - 2¹ = 81869 is a prime.

It is a Duffinian number.

81871 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520 + ... + 658.

It is an arithmetic number, because the mean of its divisors is an integer number (11200).

2⁸¹⁸⁷¹ is an apocalyptic number.

81871 is a deficient number, since it is larger than the sum of its proper divisors (7729).

81871 is a wasteful number, since it uses less digits than its factorization.

81871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189.

The product of its digits is 448, while the sum is 25.

The square root of 81871 is about 286.1310888387. The cubic root of 81871 is about 43.4220208635.

The spelling of 81871 in words is "eighty-one thousand, eight hundred seventy-one".