81775 has 6 divisors (see below), whose sum is σ = 101432. Its totient is φ = 65400.

The previous prime is 81773. The next prime is 81799. The reversal of 81775 is 57718.

It is a happy number.

It is not a de Polignac number, because 81775 - 2¹ = 81773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1611 + ... + 1660.

2⁸¹⁷⁷⁵ is an apocalyptic number.

81775 is a deficient number, since it is larger than the sum of its proper divisors (19657).

81775 is a wasteful number, since it uses less digits than its factorization.

81775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3281 (or 3276 counting only the distinct ones).

The product of its digits is 1960, while the sum is 28.

The square root of 81775 is about 285.9632843566. The cubic root of 81775 is about 43.4050423470.

The spelling of 81775 in words is "eighty-one thousand, seven hundred seventy-five".