218246681 has 2 divisors, whose sum is σ = 218246682. Its totient is φ = 218246680.

The previous prime is 218246573. The next prime is 218246729. The reversal of 218246681 is 186642812.

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., 204490000 + 13756681 = 14300^2 + 3709^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218246681 is a prime.

It is a super-2 number, since 2×218246681² = 95263227535031522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (218246381) 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, 109123340 + 109123341.

It is an arithmetic number, because the mean of its divisors is an integer number (109123341).

Almost surely, 2^218246681 is an apocalyptic number.

It is an amenable number.

218246681 is a deficient number, since it is larger than the sum of its proper divisors (1).

218246681 is an equidigital number, since it uses as much as digits as its factorization.

218246681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36864, while the sum is 38.

The square root of 218246681 is about 14773.1743711364. The cubic root of 218246681 is about 602.0730891049.

The spelling of 218246681 in words is "two hundred eighteen million, two hundred forty-six thousand, six hundred eighty-one".