18189917 has 2 divisors, whose sum is σ = 18189918. Its totient is φ = 18189916.

The previous prime is 18189889. The next prime is 18189923. The reversal of 18189917 is 71998181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16370116 + 1819801 = 4046^2 + 1349^2 .

It is a cyclic number.

It is not a de Polignac number, because 18189917 - 2¹⁰ = 18188893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18189947) 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, 9094958 + 9094959.

It is an arithmetic number, because the mean of its divisors is an integer number (9094959).

Almost surely, 2^18189917 is an apocalyptic number.

It is an amenable number.

18189917 is a deficient number, since it is larger than the sum of its proper divisors (1).

18189917 is an equidigital number, since it uses as much as digits as its factorization.

18189917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 44.

The square root of 18189917 is about 4264.9638919925. The cubic root of 18189917 is about 262.9926265480.

The spelling of 18189917 in words is "eighteen million, one hundred eighty-nine thousand, nine hundred seventeen".