81239 has 2 divisors, whose sum is σ = 81240.
Its totient is φ = 81238.
The previous prime is 81233. The next prime is 81281. The reversal of 81239 is 93218.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 81239 - 24 = 81223 is a prime.
It is a Chen prime.
It is equal to p7952 and since 81239 and 7952 have the same sum of digits, it is a Honaker prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (81233) 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, 40619 + 40620.
It is an arithmetic number, because the mean of its divisors is an integer number (40620).
281239 is an apocalyptic number.
81239 is a deficient number, since it is larger than the sum of its proper divisors (1).
81239 is an equidigital number, since it uses as much as digits as its factorization.
81239 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 432, while the sum is 23.
The square root of 81239 is about 285.0245603452.
The cubic root of 81239 is about 43.3100005880.
The spelling of 81239 in words is "eighty-one thousand, two hundred thirty-nine".