217880489 has 2 divisors, whose sum is σ = 217880490. Its totient is φ = 217880488.

The previous prime is 217880461. The next prime is 217880491. The reversal of 217880489 is 984088712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180768025 + 37112464 = 13445^2 + 6092^2 .

It is a cyclic number.

It is not a de Polignac number, because 217880489 - 2⁸ = 217880233 is a prime.

It is a Sophie Germain prime.

Together with 217880491, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (217880459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108940244 + 108940245.

It is an arithmetic number, because the mean of its divisors is an integer number (108940245).

Almost surely, 2^217880489 is an apocalyptic number.

It is an amenable number.

217880489 is a deficient number, since it is larger than the sum of its proper divisors (1).

217880489 is an equidigital number, since it uses as much as digits as its factorization.

217880489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 258048, while the sum is 47.

The square root of 217880489 is about 14760.7753522639. The cubic root of 217880489 is about 601.7361648920.

The spelling of 217880489 in words is "two hundred seventeen million, eight hundred eighty thousand, four hundred eighty-nine".