217385873 has 2 divisors, whose sum is σ = 217385874. Its totient is φ = 217385872.

The previous prime is 217385867. The next prime is 217385891. The reversal of 217385873 is 378583712.

217385873 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 175615504 + 41770369 = 13252^2 + 6463^2 .

It is a cyclic number.

It is not a de Polignac number, because 217385873 - 2⁸ = 217385617 is a prime.

It is a super-3 number, since 3×217385873³ (a number of 26 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (217385843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108692936 + 108692937.

It is an arithmetic number, because the mean of its divisors is an integer number (108692937).

Almost surely, 2^217385873 is an apocalyptic number.

It is an amenable number.

217385873 is a deficient number, since it is larger than the sum of its proper divisors (1).

217385873 is an equidigital number, since it uses as much as digits as its factorization.

217385873 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 44.

The square root of 217385873 is about 14744.0114283732. The cubic root of 217385873 is about 601.2804810771.

The spelling of 217385873 in words is "two hundred seventeen million, three hundred eighty-five thousand, eight hundred seventy-three".