81330857899 has 2 divisors, whose sum is σ = 81330857900. Its totient is φ = 81330857898.

The previous prime is 81330857869. The next prime is 81330857939. The reversal of 81330857899 is 99875803318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81330857899 - 2¹⁹ = 81330333611 is a prime.

It is a super-2 number, since 2×81330857899² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81330857869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40665428949 + 40665428950.

It is an arithmetic number, because the mean of its divisors is an integer number (40665428950).

Almost surely, 2^81330857899 is an apocalyptic number.

81330857899 is a deficient number, since it is larger than the sum of its proper divisors (1).

81330857899 is an equidigital number, since it uses as much as digits as its factorization.

81330857899 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13063680, while the sum is 61.

The spelling of 81330857899 in words is "eighty-one billion, three hundred thirty million, eight hundred fifty-seven thousand, eight hundred ninety-nine".