18566213 has 2 divisors, whose sum is σ = 18566214. Its totient is φ = 18566212.

The previous prime is 18566209. The next prime is 18566263. The reversal of 18566213 is 31266581.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15737089 + 2829124 = 3967^2 + 1682^2 .

It is an emirp because it is prime and its reverse (31266581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18566213 - 2² = 18566209 is a prime.

It is a super-2 number, since 2×18566213² = 689408530322738, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18566213.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18566203) 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, 9283106 + 9283107.

It is an arithmetic number, because the mean of its divisors is an integer number (9283107).

Almost surely, 2^18566213 is an apocalyptic number.

It is an amenable number.

18566213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18566213 is an equidigital number, since it uses as much as digits as its factorization.

18566213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 18566213 is about 4308.8528635821. The cubic root of 18566213 is about 264.7937780915.

The spelling of 18566213 in words is "eighteen million, five hundred sixty-six thousand, two hundred thirteen".