18706213 has 2 divisors, whose sum is σ = 18706214. Its totient is φ = 18706212.

The previous prime is 18706151. The next prime is 18706231. The reversal of 18706213 is 31260781.

Together with next prime (18706231) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17447329 + 1258884 = 4177^2 + 1122^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18706213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18706283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9353106 + 9353107.

It is an arithmetic number, because the mean of its divisors is an integer number (9353107).

Almost surely, 2^18706213 is an apocalyptic number.

It is an amenable number.

18706213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18706213 is an equidigital number, since it uses as much as digits as its factorization.

18706213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 18706213 is about 4325.0679763444. The cubic root of 18706213 is about 265.4576783004.

Adding to 18706213 its reverse (31260781), we get a palindrome (49966994).

The spelling of 18706213 in words is "eighteen million, seven hundred six thousand, two hundred thirteen".