81252536854817 has 2 divisors, whose sum is σ = 81252536854818. Its totient is φ = 81252536854816.

The previous prime is 81252536854751. The next prime is 81252536854873. The reversal of 81252536854817 is 71845863525218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81106667093776 + 145869761041 = 9005924^2 + 381929^2 .

It is a cyclic number.

It is not a de Polignac number, because 81252536854817 - 2⁸ = 81252536854561 is a prime.

It is a super-2 number, since 2×81252536854817² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81252836854817) 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, 40626268427408 + 40626268427409.

It is an arithmetic number, because the mean of its divisors is an integer number (40626268427409).

Almost surely, 2^{81252536854817} is an apocalyptic number.

It is an amenable number.

81252536854817 is a deficient number, since it is larger than the sum of its proper divisors (1).

81252536854817 is an equidigital number, since it uses as much as digits as its factorization.

81252536854817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024000, while the sum is 65.

The spelling of 81252536854817 in words is "eighty-one trillion, two hundred fifty-two billion, five hundred thirty-six million, eight hundred fifty-four thousand, eight hundred seventeen".