218508889 has 2 divisors, whose sum is σ = 218508890. Its totient is φ = 218508888.

The previous prime is 218508887. The next prime is 218508907. The reversal of 218508889 is 988805812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112254025 + 106254864 = 10595^2 + 10308^2 .

It is a cyclic number.

It is not a de Polignac number, because 218508889 - 2¹ = 218508887 is a prime.

It is a super-2 number, since 2×218508889² = 95492269144028642, which contains 22 as substring.

Together with 218508887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (218508883) 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, 109254444 + 109254445.

It is an arithmetic number, because the mean of its divisors is an integer number (109254445).

Almost surely, 2^218508889 is an apocalyptic number.

It is an amenable number.

218508889 is a deficient number, since it is larger than the sum of its proper divisors (1).

218508889 is an equidigital number, since it uses as much as digits as its factorization.

218508889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 368640, while the sum is 49.

The square root of 218508889 is about 14782.0461709467. The cubic root of 218508889 is about 602.3141087307.

The spelling of 218508889 in words is "two hundred eighteen million, five hundred eight thousand, eight hundred eighty-nine".