81559 has 2 divisors, whose sum is σ = 81560. Its totient is φ = 81558.

The previous prime is 81553. The next prime is 81563. The reversal of 81559 is 95518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81559 - 2³ = 81551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81551) 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, 40779 + 40780.

It is an arithmetic number, because the mean of its divisors is an integer number (40780).

2⁸¹⁵⁵⁹ is an apocalyptic number.

81559 is a deficient number, since it is larger than the sum of its proper divisors (1).

81559 is an equidigital number, since it uses as much as digits as its factorization.

81559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The square root of 81559 is about 285.5853637706. The cubic root of 81559 is about 43.3667920420.

The spelling of 81559 in words is "eighty-one thousand, five hundred fifty-nine".