81679 has 8 divisors (see below), whose sum is σ = 90272. Its totient is φ = 73440.

The previous prime is 81677. The next prime is 81689. The reversal of 81679 is 97618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81679 - 2¹ = 81677 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81671) 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 7 ways as a sum of consecutive naturals, for example, 742 + ... + 844.

It is an arithmetic number, because the mean of its divisors is an integer number (11284).

2⁸¹⁶⁷⁹ is an apocalyptic number.

81679 is a deficient number, since it is larger than the sum of its proper divisors (8593).

81679 is a wasteful number, since it uses less digits than its factorization.

81679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177.

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

The square root of 81679 is about 285.7953813483. The cubic root of 81679 is about 43.3880505374.

The spelling of 81679 in words is "eighty-one thousand, six hundred seventy-nine".