18555366355609 has 2 divisors, whose sum is σ = 18555366355610. Its totient is φ = 18555366355608.

The previous prime is 18555366355573. The next prime is 18555366355637. The reversal of 18555366355609 is 90655366355581.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18553668915609 + 1697440000 = 4307397^2 + 41200^2 .

It is an emirp because it is prime and its reverse (90655366355581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18555366355609 - 2⁷ = 18555366355481 is a prime.

It is not a weakly prime, because it can be changed into another prime (18555366355649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9277683177804 + 9277683177805.

It is an arithmetic number, because the mean of its divisors is an integer number (9277683177805).

Almost surely, 2^{18555366355609} is an apocalyptic number.

It is an amenable number.

18555366355609 is a deficient number, since it is larger than the sum of its proper divisors (1).

18555366355609 is an equidigital number, since it uses as much as digits as its factorization.

18555366355609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 437400000, while the sum is 67.

The spelling of 18555366355609 in words is "eighteen trillion, five hundred fifty-five billion, three hundred sixty-six million, three hundred fifty-five thousand, six hundred nine".