81444551899 has 2 divisors, whose sum is σ = 81444551900. Its totient is φ = 81444551898.

The previous prime is 81444551893. The next prime is 81444551917. The reversal of 81444551899 is 99815544418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81444551899 - 2⁹ = 81444551387 is a prime.

It is not a weakly prime, because it can be changed into another prime (81444551893) 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, 40722275949 + 40722275950.

It is an arithmetic number, because the mean of its divisors is an integer number (40722275950).

Almost surely, 2^81444551899 is an apocalyptic number.

81444551899 is a deficient number, since it is larger than the sum of its proper divisors (1).

81444551899 is an equidigital number, since it uses as much as digits as its factorization.

81444551899 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8294400, while the sum is 58.

The spelling of 81444551899 in words is "eighty-one billion, four hundred forty-four million, five hundred fifty-one thousand, eight hundred ninety-nine".