81693 has 12 divisors (see below), whose sum is σ = 122460. Its totient is φ = 52416.

The previous prime is 81689. The next prime is 81701. The reversal of 81693 is 39618.

It can be written as a sum of positive squares in 2 ways, for example, as 15129 + 66564 = 123^2 + 258^2 .

It is not a de Polignac number, because 81693 - 2² = 81689 is a prime.

It is a d-powerful number, because it can be written as 8⁵ + 1 + 6⁶ + 9² + 3⁷ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81293) 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 11 ways as a sum of consecutive naturals, for example, 105 + ... + 417.

It is an arithmetic number, because the mean of its divisors is an integer number (10205).

2⁸¹⁶⁹³ is an apocalyptic number.

It is an amenable number.

81693 is a deficient number, since it is larger than the sum of its proper divisors (40767).

81693 is a wasteful number, since it uses less digits than its factorization.

81693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348 (or 345 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 81693 is about 285.8198733468. The cubic root of 81693 is about 43.3905293386.

It can be divided in two parts, 816 and 93, that added together give a palindrome (909).

The spelling of 81693 in words is "eighty-one thousand, six hundred ninety-three".