81189 has 16 divisors (see below), whose sum is σ = 125440. Its totient is φ = 51840.

The previous prime is 81181. The next prime is 81197. The reversal of 81189 is 98118.

It is an interprime number because it is at equal distance from previous prime (81181) and next prime (81197).

It is not a de Polignac number, because 81189 - 2³ = 81181 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 789 + ... + 885.

It is an arithmetic number, because the mean of its divisors is an integer number (7840).

2⁸¹¹⁸⁹ is an apocalyptic number.

It is an amenable number.

81189 is a deficient number, since it is larger than the sum of its proper divisors (44251).

81189 is a wasteful number, since it uses less digits than its factorization.

81189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 131 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 81189 is about 284.9368351056. The cubic root of 81189 is about 43.3011134589.

It can be divided in two parts, 811 and 89, that added together give a square (900 = 30²).

The spelling of 81189 in words is "eighty-one thousand, one hundred eighty-nine".