218540213 has 2 divisors, whose sum is σ = 218540214. Its totient is φ = 218540212.

The previous prime is 218540197. The next prime is 218540251. The reversal of 218540213 is 312045812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216472369 + 2067844 = 14713^2 + 1438^2 .

It is a cyclic number.

It is not a de Polignac number, because 218540213 - 2⁴ = 218540197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218540813) 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, 109270106 + 109270107.

It is an arithmetic number, because the mean of its divisors is an integer number (109270107).

Almost surely, 2^218540213 is an apocalyptic number.

It is an amenable number.

218540213 is a deficient number, since it is larger than the sum of its proper divisors (1).

218540213 is an equidigital number, since it uses as much as digits as its factorization.

218540213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 218540213 is about 14783.1056615313. The cubic root of 218540213 is about 602.3428886211.

The spelling of 218540213 in words is "two hundred eighteen million, five hundred forty thousand, two hundred thirteen".