26857566809 has 2 divisors, whose sum is σ = 26857566810. Its totient is φ = 26857566808.

The previous prime is 26857566781. The next prime is 26857566847. The reversal of 26857566809 is 90866575862.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25715329600 + 1142237209 = 160360^2 + 33797^2 .

It is a cyclic number.

It is not a de Polignac number, because 26857566809 - 2¹⁶ = 26857501273 is a prime.

It is not a weakly prime, because it can be changed into another prime (26857566709) 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, 13428783404 + 13428783405.

It is an arithmetic number, because the mean of its divisors is an integer number (13428783405).

Almost surely, 2^26857566809 is an apocalyptic number.

It is an amenable number.

26857566809 is a deficient number, since it is larger than the sum of its proper divisors (1).

26857566809 is an equidigital number, since it uses as much as digits as its factorization.

26857566809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43545600, while the sum is 62.

The spelling of 26857566809 in words is "twenty-six billion, eight hundred fifty-seven million, five hundred sixty-six thousand, eight hundred nine".