217849 has 2 divisors, whose sum is σ = 217850. Its totient is φ = 217848.

The previous prime is 217829. The next prime is 217859. The reversal of 217849 is 948712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164025 + 53824 = 405^2 + 232^2 .

It is a cyclic number.

It is not a de Polignac number, because 217849 - 2⁹ = 217337 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 217849.

It is not a weakly prime, because it can be changed into another prime (217829) 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, 108924 + 108925.

It is an arithmetic number, because the mean of its divisors is an integer number (108925).

2²¹⁷⁸⁴⁹ is an apocalyptic number.

It is an amenable number.

217849 is a deficient number, since it is larger than the sum of its proper divisors (1).

217849 is an equidigital number, since it uses as much as digits as its factorization.

217849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 31.

The square root of 217849 is about 466.7429699524. The cubic root of 217849 is about 60.1707175019.

The spelling of 217849 in words is "two hundred seventeen thousand, eight hundred forty-nine".