18645181 has 2 divisors, whose sum is σ = 18645182. Its totient is φ = 18645180.

The previous prime is 18645161. The next prime is 18645191. The reversal of 18645181 is 18154681.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18404100 + 241081 = 4290^2 + 491^2 .

It is an emirp because it is prime and its reverse (18154681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18645181 - 2⁹ = 18644669 is a prime.

It is a super-2 number, since 2×18645181² = 695285549045522, which contains 22 as substring.

It is equal to p_1189861 and since 18645181 and 1189861 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18645131) 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, 9322590 + 9322591.

It is an arithmetic number, because the mean of its divisors is an integer number (9322591).

Almost surely, 2^18645181 is an apocalyptic number.

It is an amenable number.

18645181 is a deficient number, since it is larger than the sum of its proper divisors (1).

18645181 is an equidigital number, since it uses as much as digits as its factorization.

18645181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 34.

The square root of 18645181 is about 4318.0066002729. The cubic root of 18645181 is about 265.1686644324.

The spelling of 18645181 in words is "eighteen million, six hundred forty-five thousand, one hundred eighty-one".