81269 has 4 divisors (see below), whose sum is σ = 81900. Its totient is φ = 80640.

The previous prime is 81239. The next prime is 81281. The reversal of 81269 is 96218.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 96218 = 2 ⋅48109.

It can be written as a sum of positive squares in 2 ways, for example, as 18769 + 62500 = 137^2 + 250^2 .

It is a cyclic number.

It is not a de Polignac number, because 81269 - 2⁸ = 81013 is a prime.

It is a super-2 number, since 2×81269² = 13209300722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44 + ... + 405.

It is an arithmetic number, because the mean of its divisors is an integer number (20475).

2⁸¹²⁶⁹ is an apocalyptic number.

It is an amenable number.

81269 is a deficient number, since it is larger than the sum of its proper divisors (631).

81269 is a wasteful number, since it uses less digits than its factorization.

81269 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630.

The product of its digits is 864, while the sum is 26.

The square root of 81269 is about 285.0771825313. The cubic root of 81269 is about 43.3153311153.

The spelling of 81269 in words is "eighty-one thousand, two hundred sixty-nine".