217950389 has 2 divisors, whose sum is σ = 217950390. Its totient is φ = 217950388.

The previous prime is 217950347. The next prime is 217950391. The reversal of 217950389 is 983059712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194379364 + 23571025 = 13942^2 + 4855^2 .

It is a cyclic number.

It is not a de Polignac number, because 217950389 - 2¹⁶ = 217884853 is a prime.

Together with 217950391, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217950289) 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, 108975194 + 108975195.

It is an arithmetic number, because the mean of its divisors is an integer number (108975195).

Almost surely, 2^217950389 is an apocalyptic number.

It is an amenable number.

217950389 is a deficient number, since it is larger than the sum of its proper divisors (1).

217950389 is an equidigital number, since it uses as much as digits as its factorization.

217950389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 136080, while the sum is 44.

The square root of 217950389 is about 14763.1429241879. The cubic root of 217950389 is about 601.8005072920.

The spelling of 217950389 in words is "two hundred seventeen million, nine hundred fifty thousand, three hundred eighty-nine".