81599349739 has 2 divisors, whose sum is σ = 81599349740. Its totient is φ = 81599349738.

The previous prime is 81599349721. The next prime is 81599349773. The reversal of 81599349739 is 93794399518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81599349739 - 2¹¹ = 81599347691 is a prime.

It is not a weakly prime, because it can be changed into another prime (81599349779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40799674869 + 40799674870.

It is an arithmetic number, because the mean of its divisors is an integer number (40799674870).

Almost surely, 2^81599349739 is an apocalyptic number.

81599349739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81599349739 is an equidigital number, since it uses as much as digits as its factorization.

81599349739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 66134880, while the sum is 67.

The spelling of 81599349739 in words is "eighty-one billion, five hundred ninety-nine million, three hundred forty-nine thousand, seven hundred thirty-nine".