81559839 has 8 divisors (see below), whose sum is σ = 108943920. Its totient is φ = 54274496.

The previous prime is 81559813. The next prime is 81559843. The reversal of 81559839 is 93895518.

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 81559839 - 2⁹ = 81559327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81559139) 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 in 7 ways as a sum of consecutive naturals, for example, 22734 + ... + 26075.

It is an arithmetic number, because the mean of its divisors is an integer number (13617990).

Almost surely, 2^81559839 is an apocalyptic number.

81559839 is a deficient number, since it is larger than the sum of its proper divisors (27384081).

81559839 is a wasteful number, since it uses less digits than its factorization.

81559839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49369.

The product of its digits is 388800, while the sum is 48.

The square root of 81559839 is about 9031.0486102113. The cubic root of 81559839 is about 433.6694074672.

The spelling of 81559839 in words is "eighty-one million, five hundred fifty-nine thousand, eight hundred thirty-nine".