6566665409 has 2 divisors, whose sum is σ = 6566665410. Its totient is φ = 6566665408.

The previous prime is 6566665403. The next prime is 6566665421. The reversal of 6566665409 is 9045666656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5791210000 + 775455409 = 76100^2 + 27847^2 .

It is a cyclic number.

It is not a de Polignac number, because 6566665409 - 2¹⁶ = 6566599873 is a prime.

It is not a weakly prime, because it can be changed into another prime (6566665403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3283332704 + 3283332705.

It is an arithmetic number, because the mean of its divisors is an integer number (3283332705).

Almost surely, 2^6566665409 is an apocalyptic number.

It is an amenable number.

6566665409 is a deficient number, since it is larger than the sum of its proper divisors (1).

6566665409 is an equidigital number, since it uses as much as digits as its factorization.

6566665409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6998400, while the sum is 53.

The square root of 6566665409 is about 81034.9641142637. The cubic root of 6566665409 is about 1872.6141300594.

The spelling of 6566665409 in words is "six billion, five hundred sixty-six million, six hundred sixty-five thousand, four hundred nine".