8205581 has 2 divisors, whose sum is σ = 8205582. Its totient is φ = 8205580.

The previous prime is 8205569. The next prime is 8205599. The reversal of 8205581 is 1855028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8094025 + 111556 = 2845^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 8205581 - 2¹⁴ = 8189197 is a prime.

It is a super-2 number, since 2×8205581² = 134663119095122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8205881) 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, 4102790 + 4102791.

It is an arithmetic number, because the mean of its divisors is an integer number (4102791).

Almost surely, 2^8205581 is an apocalyptic number.

It is an amenable number.

8205581 is a deficient number, since it is larger than the sum of its proper divisors (1).

8205581 is an equidigital number, since it uses as much as digits as its factorization.

8205581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 8205581 is about 2864.5385317709. The cubic root of 8205581 is about 201.6987061390.

The spelling of 8205581 in words is "eight million, two hundred five thousand, five hundred eighty-one".