81000018000089 has 2 divisors, whose sum is σ = 81000018000090. Its totient is φ = 81000018000088.

The previous prime is 81000018000029. The next prime is 81000018000107. The reversal of 81000018000089 is 98000081000018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53976572265625 + 27023445734464 = 7346875^2 + 5198408^2 .

It is a cyclic number.

It is not a de Polignac number, because 81000018000089 - 2⁸ = 81000017999833 is a prime.

It is a super-2 number, since 2×81000018000089² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81000018000029) 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, 40500009000044 + 40500009000045.

It is an arithmetic number, because the mean of its divisors is an integer number (40500009000045).

Almost surely, 2^{81000018000089} is an apocalyptic number.

It is an amenable number.

81000018000089 is a deficient number, since it is larger than the sum of its proper divisors (1).

81000018000089 is an equidigital number, since it uses as much as digits as its factorization.

81000018000089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 35.

The spelling of 81000018000089 in words is "eighty-one trillion, eighteen million, eighty-nine", and thus it is an aban number and an uban number.