81058165 has 4 divisors (see below), whose sum is σ = 97269804. Its totient is φ = 64846528.

The previous prime is 81058163. The next prime is 81058169. The reversal of 81058165 is 56185018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11985444 + 69072721 = 3462^2 + 8311^2 .

It is a cyclic number.

It is not a de Polignac number, because 81058165 - 2¹ = 81058163 is a prime.

It is a super-2 number, since 2×81058165² = 13140852226334450, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81058165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81058163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8105812 + ... + 8105821.

It is an arithmetic number, because the mean of its divisors is an integer number (24317451).

Almost surely, 2^81058165 is an apocalyptic number.

It is an amenable number.

81058165 is a deficient number, since it is larger than the sum of its proper divisors (16211639).

81058165 is a wasteful number, since it uses less digits than its factorization.

81058165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16211638.

The product of its (nonzero) digits is 9600, while the sum is 34.

The square root of 81058165 is about 9003.2308089930. The cubic root of 81058165 is about 432.7784122954.

The spelling of 81058165 in words is "eighty-one million, fifty-eight thousand, one hundred sixty-five".