81065871 has 6 divisors (see below), whose sum is σ = 117095160. Its totient is φ = 54043908.

The previous prime is 81065863. The next prime is 81065891. The reversal of 81065871 is 17856018.

It is not a de Polignac number, because 81065871 - 2³ = 81065863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81065801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4503651 + ... + 4503668.

It is an arithmetic number, because the mean of its divisors is an integer number (19515860).

Almost surely, 2^81065871 is an apocalyptic number.

81065871 is a deficient number, since it is larger than the sum of its proper divisors (36029289).

81065871 is a wasteful number, since it uses less digits than its factorization.

81065871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9007325 (or 9007322 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 36.

The square root of 81065871 is about 9003.6587563057. The cubic root of 81065871 is about 432.7921262532.

The spelling of 81065871 in words is "eighty-one million, sixty-five thousand, eight hundred seventy-one".