81769 has 2 divisors, whose sum is σ = 81770. Its totient is φ = 81768.

The previous prime is 81761. The next prime is 81773. The reversal of 81769 is 96718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56169 + 25600 = 237^2 + 160^2 .

It is a cyclic number.

It is not a de Polignac number, because 81769 - 2³ = 81761 is a prime.

It is a super-2 number, since 2×81769² = 13372338722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81769.

It is not a weakly prime, because it can be changed into another prime (81761) 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 as a sum of consecutive naturals, namely, 40884 + 40885.

It is an arithmetic number, because the mean of its divisors is an integer number (40885).

2⁸¹⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

81769 is a deficient number, since it is larger than the sum of its proper divisors (1).

81769 is an equidigital number, since it uses as much as digits as its factorization.

81769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 31.

The square root of 81769 is about 285.9527933069. The cubic root of 81769 is about 43.4039807486.

The spelling of 81769 in words is "eighty-one thousand, seven hundred sixty-nine".