81636099529 has 2 divisors, whose sum is σ = 81636099530. Its totient is φ = 81636099528.

The previous prime is 81636099511. The next prime is 81636099533. The reversal of 81636099529 is 92599063618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57721023504 + 23915076025 = 240252^2 + 154645^2 .

It is a cyclic number.

It is not a de Polignac number, because 81636099529 - 2⁷ = 81636099401 is a prime.

It is not a weakly prime, because it can be changed into another prime (81636099569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40818049764 + 40818049765.

It is an arithmetic number, because the mean of its divisors is an integer number (40818049765).

Almost surely, 2^81636099529 is an apocalyptic number.

It is an amenable number.

81636099529 is a deficient number, since it is larger than the sum of its proper divisors (1).

81636099529 is an equidigital number, since it uses as much as digits as its factorization.

81636099529 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6298560, while the sum is 58.

The spelling of 81636099529 in words is "eighty-one billion, six hundred thirty-six million, ninety-nine thousand, five hundred twenty-nine".