18365181817 has 2 divisors, whose sum is σ = 18365181818. Its totient is φ = 18365181816.

The previous prime is 18365181811. The next prime is 18365181847. The reversal of 18365181817 is 71818156381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15532387641 + 2832794176 = 124629^2 + 53224^2 .

It is an emirp because it is prime and its reverse (71818156381) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18365181817 is a prime.

It is not a weakly prime, because it can be changed into another prime (18365181811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9182590908 + 9182590909.

It is an arithmetic number, because the mean of its divisors is an integer number (9182590909).

Almost surely, 2^18365181817 is an apocalyptic number.

It is an amenable number.

18365181817 is a deficient number, since it is larger than the sum of its proper divisors (1).

18365181817 is an equidigital number, since it uses as much as digits as its factorization.

18365181817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 49.

The spelling of 18365181817 in words is "eighteen billion, three hundred sixty-five million, one hundred eighty-one thousand, eight hundred seventeen".