81598886513 has 2 divisors, whose sum is σ = 81598886514. Its totient is φ = 81598886512.

The previous prime is 81598886477. The next prime is 81598886531. The reversal of 81598886513 is 31568889518.

Together with next prime (81598886531) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78300911329 + 3297975184 = 279823^2 + 57428^2 .

It is a cyclic number.

It is not a de Polignac number, because 81598886513 - 2¹⁸ = 81598624369 is a prime.

It is a super-2 number, since 2×81598886513² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81598886563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40799443256 + 40799443257.

It is an arithmetic number, because the mean of its divisors is an integer number (40799443257).

Almost surely, 2^81598886513 is an apocalyptic number.

It is an amenable number.

81598886513 is a deficient number, since it is larger than the sum of its proper divisors (1).

81598886513 is an equidigital number, since it uses as much as digits as its factorization.

81598886513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16588800, while the sum is 62.

The spelling of 81598886513 in words is "eighty-one billion, five hundred ninety-eight million, eight hundred eighty-six thousand, five hundred thirteen".