18442213 has 2 divisors, whose sum is σ = 18442214. Its totient is φ = 18442212.

The previous prime is 18442201. The next prime is 18442223. The reversal of 18442213 is 31224481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15507844 + 2934369 = 3938^2 + 1713^2 .

It is an emirp because it is prime and its reverse (31224481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18442213 - 2⁵ = 18442181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18442223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9221106 + 9221107.

It is an arithmetic number, because the mean of its divisors is an integer number (9221107).

Almost surely, 2^18442213 is an apocalyptic number.

It is an amenable number.

18442213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18442213 is an equidigital number, since it uses as much as digits as its factorization.

18442213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 25.

The square root of 18442213 is about 4294.4397772003. The cubic root of 18442213 is about 264.2029593625.

Adding to 18442213 its reverse (31224481), we get a palindrome (49666694).

The spelling of 18442213 in words is "eighteen million, four hundred forty-two thousand, two hundred thirteen".