218642813 has 2 divisors, whose sum is σ = 218642814. Its totient is φ = 218642812.

The previous prime is 218642779. The next prime is 218642843. The reversal of 218642813 is 318246812.

218642813 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131836324 + 86806489 = 11482^2 + 9317^2 .

It is a cyclic number.

It is not a de Polignac number, because 218642813 - 2¹⁶ = 218577277 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218642843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109321406 + 109321407.

It is an arithmetic number, because the mean of its divisors is an integer number (109321407).

Almost surely, 2^218642813 is an apocalyptic number.

It is an amenable number.

218642813 is a deficient number, since it is larger than the sum of its proper divisors (1).

218642813 is an equidigital number, since it uses as much as digits as its factorization.

218642813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 35.

The square root of 218642813 is about 14786.5754317895. The cubic root of 218642813 is about 602.4371362819.

The spelling of 218642813 in words is "two hundred eighteen million, six hundred forty-two thousand, eight hundred thirteen".