18091209109 has 2 divisors, whose sum is σ = 18091209110. Its totient is φ = 18091209108.

The previous prime is 18091209091. The next prime is 18091209127. The reversal of 18091209109 is 90190219081.

Together with previous prime (18091209091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (18091209091) and next prime (18091209127).

It can be written as a sum of positive squares in only one way, i.e., 18091057009 + 152100 = 134503^2 + 390^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18091209109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18091209179) 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, 9045604554 + 9045604555.

It is an arithmetic number, because the mean of its divisors is an integer number (9045604555).

Almost surely, 2^18091209109 is an apocalyptic number.

It is an amenable number.

18091209109 is a deficient number, since it is larger than the sum of its proper divisors (1).

18091209109 is an equidigital number, since it uses as much as digits as its factorization.

18091209109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 40.

The spelling of 18091209109 in words is "eighteen billion, ninety-one million, two hundred nine thousand, one hundred nine".