81717 has 4 divisors (see below), whose sum is σ = 108960. Its totient is φ = 54476.

The previous prime is 81707. The next prime is 81727. The reversal of 81717 is 71718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (81707) and next prime (81727).

It is a cyclic number.

It is not a de Polignac number, because 81717 - 2⁴ = 81701 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81707) 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, 13617 + ... + 13622.

It is an arithmetic number, because the mean of its divisors is an integer number (27240).

2⁸¹⁷¹⁷ is an apocalyptic number.

It is an amenable number.

81717 is a deficient number, since it is larger than the sum of its proper divisors (27243).

81717 is a wasteful number, since it uses less digits than its factorization.

81717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27242.

The product of its digits is 392, while the sum is 24.

The square root of 81717 is about 285.8618547481. The cubic root of 81717 is about 43.3947780532.

Subtracting from 81717 its reverse (71718), we obtain a palindrome (9999).

The spelling of 81717 in words is "eighty-one thousand, seven hundred seventeen".