8165581 has 2 divisors, whose sum is σ = 8165582. Its totient is φ = 8165580.

The previous prime is 8165569. The next prime is 8165609. The reversal of 8165581 is 1855618.

8165581 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5103081 + 3062500 = 2259^2 + 1750^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8165581 is a prime.

It is a super-3 number, since 3×8165581³ (a number of 22 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8165681) 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, 4082790 + 4082791.

It is an arithmetic number, because the mean of its divisors is an integer number (4082791).

Almost surely, 2^8165581 is an apocalyptic number.

It is an amenable number.

8165581 is a deficient number, since it is larger than the sum of its proper divisors (1).

8165581 is an equidigital number, since it uses as much as digits as its factorization.

8165581 is an odious number, because the sum of its binary digits is odd.

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

The square root of 8165581 is about 2857.5480748362. The cubic root of 8165581 is about 201.3704298290.

The spelling of 8165581 in words is "eight million, one hundred sixty-five thousand, five hundred eighty-one".