8166581 has 2 divisors, whose sum is σ = 8166582. Its totient is φ = 8166580.

The previous prime is 8166577. The next prime is 8166589. The reversal of 8166581 is 1856618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4202500 + 3964081 = 2050^2 + 1991^2 .

It is a cyclic number.

It is not a de Polignac number, because 8166581 - 2² = 8166577 is a prime.

It is a super-2 number, since 2×8166581² = 133386090459122, which contains 22 as substring.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8166589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4083290 + 4083291.

It is an arithmetic number, because the mean of its divisors is an integer number (4083291).

Almost surely, 2^8166581 is an apocalyptic number.

It is an amenable number.

8166581 is a deficient number, since it is larger than the sum of its proper divisors (1).

8166581 is an equidigital number, since it uses as much as digits as its factorization.

8166581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 35.

The square root of 8166581 is about 2857.7230446634. The cubic root of 8166581 is about 201.3786497874.

The spelling of 8166581 in words is "eight million, one hundred sixty-six thousand, five hundred eighty-one".