218458813 has 2 divisors, whose sum is σ = 218458814. Its totient is φ = 218458812.

The previous prime is 218458811. The next prime is 218458831. The reversal of 218458813 is 318854812.

Together with next prime (218458831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 171426649 + 47032164 = 13093^2 + 6858^2 .

It is a cyclic number.

It is not a de Polignac number, because 218458813 - 2¹ = 218458811 is a prime.

Together with 218458811, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218458811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109229406 + 109229407.

It is an arithmetic number, because the mean of its divisors is an integer number (109229407).

Almost surely, 2^218458813 is an apocalyptic number.

It is an amenable number.

218458813 is a deficient number, since it is larger than the sum of its proper divisors (1).

218458813 is an equidigital number, since it uses as much as digits as its factorization.

218458813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61440, while the sum is 40.

The square root of 218458813 is about 14780.3522623786. The cubic root of 218458813 is about 602.2680941486.

The spelling of 218458813 in words is "two hundred eighteen million, four hundred fifty-eight thousand, eight hundred thirteen".