81636367259479 has 2 divisors, whose sum is σ = 81636367259480. Its totient is φ = 81636367259478.

The previous prime is 81636367259477. The next prime is 81636367259539. The reversal of 81636367259479 is 97495276363618.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81636367259479 - 2¹ = 81636367259477 is a prime.

Together with 81636367259477, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81636367259477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40818183629739 + 40818183629740.

It is an arithmetic number, because the mean of its divisors is an integer number (40818183629740).

Almost surely, 2^{81636367259479} is an apocalyptic number.

81636367259479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81636367259479 is an equidigital number, since it uses as much as digits as its factorization.

81636367259479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2469035520, while the sum is 76.

The spelling of 81636367259479 in words is "eighty-one trillion, six hundred thirty-six billion, three hundred sixty-seven million, two hundred fifty-nine thousand, four hundred seventy-nine".