18504915217 has 2 divisors, whose sum is σ = 18504915218. Its totient is φ = 18504915216.

The previous prime is 18504915161. The next prime is 18504915241. The reversal of 18504915217 is 71251940581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18462287376 + 42627841 = 135876^2 + 6529^2 .

It is a cyclic number.

It is not a de Polignac number, because 18504915217 - 2¹⁹ = 18504390929 is a prime.

It is not a weakly prime, because it can be changed into another prime (18504915257) 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, 9252457608 + 9252457609.

It is an arithmetic number, because the mean of its divisors is an integer number (9252457609).

Almost surely, 2^18504915217 is an apocalyptic number.

It is an amenable number.

18504915217 is a deficient number, since it is larger than the sum of its proper divisors (1).

18504915217 is an equidigital number, since it uses as much as digits as its factorization.

18504915217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 43.

The spelling of 18504915217 in words is "eighteen billion, five hundred four million, nine hundred fifteen thousand, two hundred seventeen".