81289 has 8 divisors (see below), whose sum is σ = 90440. Its totient is φ = 73008.

The previous prime is 81283. The next prime is 81293. The reversal of 81289 is 98218.

It can be written as a sum of positive squares in 4 ways, for example, as 10000 + 71289 = 100^2 + 267^2 .

It is not a de Polignac number, because 81289 - 2³ = 81281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2179 + ... + 2215.

It is an arithmetic number, because the mean of its divisors is an integer number (11305).

2⁸¹²⁸⁹ is an apocalyptic number.

It is an amenable number.

81289 is a deficient number, since it is larger than the sum of its proper divisors (9151).

81289 is an equidigital number, since it uses as much as digits as its factorization.

81289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76 (or 50 counting only the distinct ones).

The product of its digits is 1152, while the sum is 28.

The square root of 81289 is about 285.1122585930. The cubic root of 81289 is about 43.3188840714.

It can be divided in two parts, 81 and 289, that multiplied together give a square (23409 = 153²).

The spelling of 81289 in words is "eighty-one thousand, two hundred eighty-nine".