81847 has 2 divisors, whose sum is σ = 81848. Its totient is φ = 81846.

The previous prime is 81839. The next prime is 81853. The reversal of 81847 is 74818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81847 - 2³ = 81839 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81817) 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 as a sum of consecutive naturals, namely, 40923 + 40924.

It is an arithmetic number, because the mean of its divisors is an integer number (40924).

2⁸¹⁸⁴⁷ is an apocalyptic number.

81847 is a deficient number, since it is larger than the sum of its proper divisors (1).

81847 is an equidigital number, since it uses as much as digits as its factorization.

81847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 28.

The square root of 81847 is about 286.0891469455. The cubic root of 81847 is about 43.4177774792.

The spelling of 81847 in words is "eighty-one thousand, eight hundred forty-seven".