218857 has 2 divisors, whose sum is σ = 218858. Its totient is φ = 218856.

The previous prime is 218849. The next prime is 218873. The reversal of 218857 is 758812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177241 + 41616 = 421^2 + 204^2 .

It is a cyclic number.

It is not a de Polignac number, because 218857 - 2³ = 218849 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218887) 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, 109428 + 109429.

It is an arithmetic number, because the mean of its divisors is an integer number (109429).

2²¹⁸⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

218857 is a deficient number, since it is larger than the sum of its proper divisors (1).

218857 is an equidigital number, since it uses as much as digits as its factorization.

218857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4480, while the sum is 31.

The square root of 218857 is about 467.8215471737. The cubic root of 218857 is about 60.2633792019.

The spelling of 218857 in words is "two hundred eighteen thousand, eight hundred fifty-seven".