81273021317 has 2 divisors, whose sum is σ = 81273021318. Its totient is φ = 81273021316.

The previous prime is 81273021299. The next prime is 81273021413. The reversal of 81273021317 is 71312037218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69024951076 + 12248070241 = 262726^2 + 110671^2 .

It is a cyclic number.

It is not a de Polignac number, because 81273021317 - 2²⁴ = 81256244101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81273021517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40636510658 + 40636510659.

It is an arithmetic number, because the mean of its divisors is an integer number (40636510659).

Almost surely, 2^81273021317 is an apocalyptic number.

It is an amenable number.

81273021317 is a deficient number, since it is larger than the sum of its proper divisors (1).

81273021317 is an equidigital number, since it uses as much as digits as its factorization.

81273021317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14112, while the sum is 35.

The spelling of 81273021317 in words is "eighty-one billion, two hundred seventy-three million, twenty-one thousand, three hundred seventeen".