18920271817 has 2 divisors, whose sum is σ = 18920271818. Its totient is φ = 18920271816.

The previous prime is 18920271793. The next prime is 18920271871. The reversal of 18920271817 is 71817202981.

Together with next prime (18920271871) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11928134656 + 6992137161 = 109216^2 + 83619^2 .

It is an emirp because it is prime and its reverse (71817202981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18920271817 - 2¹⁵ = 18920239049 is a prime.

It is not a weakly prime, because it can be changed into another prime (18920272817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9460135908 + 9460135909.

It is an arithmetic number, because the mean of its divisors is an integer number (9460135909).

Almost surely, 2^18920271817 is an apocalyptic number.

It is an amenable number.

18920271817 is a deficient number, since it is larger than the sum of its proper divisors (1).

18920271817 is an equidigital number, since it uses as much as digits as its factorization.

18920271817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112896, while the sum is 46.

The spelling of 18920271817 in words is "eighteen billion, nine hundred twenty million, two hundred seventy-one thousand, eight hundred seventeen".