81760085909 has 2 divisors, whose sum is σ = 81760085910. Its totient is φ = 81760085908.

The previous prime is 81760085893. The next prime is 81760085929. The reversal of 81760085909 is 90958006718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50065405009 + 31694680900 = 223753^2 + 178030^2 .

It is a cyclic number.

It is not a de Polignac number, because 81760085909 - 2⁴ = 81760085893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81760085929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40880042954 + 40880042955.

It is an arithmetic number, because the mean of its divisors is an integer number (40880042955).

Almost surely, 2^81760085909 is an apocalyptic number.

It is an amenable number.

81760085909 is a deficient number, since it is larger than the sum of its proper divisors (1).

81760085909 is an equidigital number, since it uses as much as digits as its factorization.

81760085909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The spelling of 81760085909 in words is "eighty-one billion, seven hundred sixty million, eighty-five thousand, nine hundred nine".