81225782317 has 2 divisors, whose sum is σ = 81225782318. Its totient is φ = 81225782316.

The previous prime is 81225782311. The next prime is 81225782333. The reversal of 81225782317 is 71328752218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48007439236 + 33218343081 = 219106^2 + 182259^2 .

It is a cyclic number.

It is not a de Polignac number, because 81225782317 - 2¹⁹ = 81225258029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81225782311) 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, 40612891158 + 40612891159.

It is an arithmetic number, because the mean of its divisors is an integer number (40612891159).

Almost surely, 2^81225782317 is an apocalyptic number.

It is an amenable number.

81225782317 is a deficient number, since it is larger than the sum of its proper divisors (1).

81225782317 is an equidigital number, since it uses as much as digits as its factorization.

81225782317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 376320, while the sum is 46.

The spelling of 81225782317 in words is "eighty-one billion, two hundred twenty-five million, seven hundred eighty-two thousand, three hundred seventeen".