81717505073 has 2 divisors, whose sum is σ = 81717505074. Its totient is φ = 81717505072.

The previous prime is 81717505063. The next prime is 81717505097. The reversal of 81717505073 is 37050571718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66392798224 + 15324706849 = 257668^2 + 123793^2 .

It is a cyclic number.

It is not a de Polignac number, because 81717505073 - 2³⁴ = 64537635889 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81717505063) 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, 40858752536 + 40858752537.

It is an arithmetic number, because the mean of its divisors is an integer number (40858752537).

Almost surely, 2^81717505073 is an apocalyptic number.

It is an amenable number.

81717505073 is a deficient number, since it is larger than the sum of its proper divisors (1).

81717505073 is an equidigital number, since it uses as much as digits as its factorization.

81717505073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 205800, while the sum is 44.

The spelling of 81717505073 in words is "eighty-one billion, seven hundred seventeen million, five hundred five thousand, seventy-three".