18118213 has 2 divisors, whose sum is σ = 18118214. Its totient is φ = 18118212.

The previous prime is 18118211. The next prime is 18118223. The reversal of 18118213 is 31281181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13198689 + 4919524 = 3633^2 + 2218^2 .

It is an emirp because it is prime and its reverse (31281181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18118213 - 2¹ = 18118211 is a prime.

Together with 18118211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18118211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9059106 + 9059107.

It is an arithmetic number, because the mean of its divisors is an integer number (9059107).

Almost surely, 2^18118213 is an apocalyptic number.

It is an amenable number.

18118213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18118213 is an equidigital number, since it uses as much as digits as its factorization.

18118213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 25.

The square root of 18118213 is about 4256.5494241228. The cubic root of 18118213 is about 262.6466023121.

Adding to 18118213 its reverse (31281181), we get a palindrome (49399394).

The spelling of 18118213 in words is "eighteen million, one hundred eighteen thousand, two hundred thirteen".