81116439329 has 2 divisors, whose sum is σ = 81116439330. Its totient is φ = 81116439328.

The previous prime is 81116439319. The next prime is 81116439337. The reversal of 81116439329 is 92393461118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80443140625 + 673298704 = 283625^2 + 25948^2 .

It is a cyclic number.

It is not a de Polignac number, because 81116439329 - 2²⁰ = 81115390753 is a prime.

It is not a weakly prime, because it can be changed into another prime (81116439319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40558219664 + 40558219665.

It is an arithmetic number, because the mean of its divisors is an integer number (40558219665).

Almost surely, 2^81116439329 is an apocalyptic number.

It is an amenable number.

81116439329 is a deficient number, since it is larger than the sum of its proper divisors (1).

81116439329 is an equidigital number, since it uses as much as digits as its factorization.

81116439329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The spelling of 81116439329 in words is "eighty-one billion, one hundred sixteen million, four hundred thirty-nine thousand, three hundred twenty-nine".