218342321 has 2 divisors, whose sum is σ = 218342322. Its totient is φ = 218342320.

The previous prime is 218342287. The next prime is 218342323. The reversal of 218342321 is 123243812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200533921 + 17808400 = 14161^2 + 4220^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218342321 is a prime.

It is a Sophie Germain prime.

Together with 218342323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (218342323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109171160 + 109171161.

It is an arithmetic number, because the mean of its divisors is an integer number (109171161).

Almost surely, 2^218342321 is an apocalyptic number.

It is an amenable number.

218342321 is a deficient number, since it is larger than the sum of its proper divisors (1).

218342321 is an equidigital number, since it uses as much as digits as its factorization.

218342321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 26.

The square root of 218342321 is about 14776.4109647776. The cubic root of 218342321 is about 602.1610230287.

The spelling of 218342321 in words is "two hundred eighteen million, three hundred forty-two thousand, three hundred twenty-one".