18689213 has 2 divisors, whose sum is σ = 18689214. Its totient is φ = 18689212.

The previous prime is 18689197. The next prime is 18689227. The reversal of 18689213 is 31298681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10640644 + 8048569 = 3262^2 + 2837^2 .

It is a cyclic number.

It is not a de Polignac number, because 18689213 - 2⁴ = 18689197 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18689233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9344606 + 9344607.

It is an arithmetic number, because the mean of its divisors is an integer number (9344607).

Almost surely, 2^18689213 is an apocalyptic number.

It is an amenable number.

18689213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18689213 is an equidigital number, since it uses as much as digits as its factorization.

18689213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 38.

The square root of 18689213 is about 4323.1022426031. The cubic root of 18689213 is about 265.3772389249.

The spelling of 18689213 in words is "eighteen million, six hundred eighty-nine thousand, two hundred thirteen".