18505434217 has 2 divisors, whose sum is σ = 18505434218. Its totient is φ = 18505434216.

The previous prime is 18505434197. The next prime is 18505434229. The reversal of 18505434217 is 71243450581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18230670441 + 274763776 = 135021^2 + 16576^2 .

It is a cyclic number.

It is not a de Polignac number, because 18505434217 - 2⁷ = 18505434089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18505434217.

It is not a weakly prime, because it can be changed into another prime (18505434257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9252717108 + 9252717109.

It is an arithmetic number, because the mean of its divisors is an integer number (9252717109).

Almost surely, 2^18505434217 is an apocalyptic number.

It is an amenable number.

18505434217 is a deficient number, since it is larger than the sum of its proper divisors (1).

18505434217 is an equidigital number, since it uses as much as digits as its factorization.

18505434217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 134400, while the sum is 40.

Adding to 18505434217 its reverse (71243450581), we get a palindrome (89748884798).

The spelling of 18505434217 in words is "eighteen billion, five hundred five million, four hundred thirty-four thousand, two hundred seventeen".