18555816193 has 2 divisors, whose sum is σ = 18555816194. Its totient is φ = 18555816192.

The previous prime is 18555816161. The next prime is 18555816241. The reversal of 18555816193 is 39161855581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18097513729 + 458302464 = 134527^2 + 21408^2 .

It is a cyclic number.

It is not a de Polignac number, because 18555816193 - 2⁵ = 18555816161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18555816193.

It is not a weakly prime, because it can be changed into another prime (18555816143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9277908096 + 9277908097.

It is an arithmetic number, because the mean of its divisors is an integer number (9277908097).

Almost surely, 2^18555816193 is an apocalyptic number.

It is an amenable number.

18555816193 is a deficient number, since it is larger than the sum of its proper divisors (1).

18555816193 is an equidigital number, since it uses as much as digits as its factorization.

18555816193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296000, while the sum is 52.

The spelling of 18555816193 in words is "eighteen billion, five hundred fifty-five million, eight hundred sixteen thousand, one hundred ninety-three".