81165 has 16 divisors (see below), whose sum is σ = 148608. Its totient is φ = 37056.

The previous prime is 81163. The next prime is 81173. The reversal of 81165 is 56118.

It is not a de Polignac number, because 81165 - 2¹ = 81163 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

81165 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81163) 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, 282 + ... + 491.

It is an arithmetic number, because the mean of its divisors is an integer number (9288).

2⁸¹¹⁶⁵ is an apocalyptic number.

It is an amenable number.

81165 is a deficient number, since it is larger than the sum of its proper divisors (67443).

81165 is a wasteful number, since it uses less digits than its factorization.

81165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 788.

The product of its digits is 240, while the sum is 21.

The square root of 81165 is about 284.8947173957. The cubic root of 81165 is about 43.2968463409.

The spelling of 81165 in words is "eighty-one thousand, one hundred sixty-five".