218961217 has 2 divisors, whose sum is σ = 218961218. Its totient is φ = 218961216.

The previous prime is 218961181. The next prime is 218961229. The reversal of 218961217 is 712169812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 218921616 + 39601 = 14796^2 + 199^2 .

It is a cyclic number.

It is not a de Polignac number, because 218961217 - 2¹⁵ = 218928449 is a prime.

It is not a weakly prime, because it can be changed into another prime (218961257) 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, 109480608 + 109480609.

It is an arithmetic number, because the mean of its divisors is an integer number (109480609).

Almost surely, 2^218961217 is an apocalyptic number.

It is an amenable number.

218961217 is a deficient number, since it is larger than the sum of its proper divisors (1).

218961217 is an equidigital number, since it uses as much as digits as its factorization.

218961217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 37.

The square root of 218961217 is about 14797.3381727931. The cubic root of 218961217 is about 602.7294324294.

The spelling of 218961217 in words is "two hundred eighteen million, nine hundred sixty-one thousand, two hundred seventeen".