81192777317 has 2 divisors, whose sum is σ = 81192777318. Its totient is φ = 81192777316.

The previous prime is 81192777293. The next prime is 81192777353. The reversal of 81192777317 is 71377729118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81157184161 + 35593156 = 284881^2 + 5966^2 .

It is a cyclic number.

It is not a de Polignac number, because 81192777317 - 2¹⁰ = 81192776293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81192770317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40596388658 + 40596388659.

It is an arithmetic number, because the mean of its divisors is an integer number (40596388659).

Almost surely, 2^81192777317 is an apocalyptic number.

It is an amenable number.

81192777317 is a deficient number, since it is larger than the sum of its proper divisors (1).

81192777317 is an equidigital number, since it uses as much as digits as its factorization.

81192777317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1037232, while the sum is 53.

The spelling of 81192777317 in words is "eighty-one billion, one hundred ninety-two million, seven hundred seventy-seven thousand, three hundred seventeen".