6605561 has 2 divisors, whose sum is σ = 6605562. Its totient is φ = 6605560.

The previous prime is 6605527. The next prime is 6605563. The reversal of 6605561 is 1655066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6175225 + 430336 = 2485^2 + 656^2 .

It is a cyclic number.

It is not a de Polignac number, because 6605561 - 2¹⁸ = 6343417 is a prime.

It is a super-2 number, since 2×6605561² = 87266872249442, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 6605563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6605563) 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, 3302780 + 3302781.

It is an arithmetic number, because the mean of its divisors is an integer number (3302781).

Almost surely, 2^6605561 is an apocalyptic number.

It is an amenable number.

6605561 is a deficient number, since it is larger than the sum of its proper divisors (1).

6605561 is an equidigital number, since it uses as much as digits as its factorization.

6605561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 6605561 is about 2570.1285960045. The cubic root of 6605561 is about 187.6304135675.

The spelling of 6605561 in words is "six million, six hundred five thousand, five hundred sixty-one".