18668213 has 2 divisors, whose sum is σ = 18668214. Its totient is φ = 18668212.

The previous prime is 18668207. The next prime is 18668263. The reversal of 18668213 is 31286681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17497489 + 1170724 = 4183^2 + 1082^2 .

It is a cyclic number.

It is not a de Polignac number, because 18668213 - 2⁴ = 18668197 is a prime.

It is a super-2 number, since 2×18668213² = 697004353226738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18668263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9334106 + 9334107.

It is an arithmetic number, because the mean of its divisors is an integer number (9334107).

Almost surely, 2^18668213 is an apocalyptic number.

It is an amenable number.

18668213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18668213 is an equidigital number, since it uses as much as digits as its factorization.

18668213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 35.

The square root of 18668213 is about 4320.6727485428. The cubic root of 18668213 is about 265.2778052632.

It can be divided in two parts, 18668 and 213, that added together give a palindrome (18881).

The spelling of 18668213 in words is "eighteen million, six hundred sixty-eight thousand, two hundred thirteen".