217128 has 32 divisors (see below), whose sum is σ = 554400. Its totient is φ = 70848.

The previous prime is 217121. The next prime is 217157. The reversal of 217128 is 821712.

It is not an unprimeable number, because it can be changed into a prime (217121) by changing a digit.

217128 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1938 + ... + 2046.

It is an arithmetic number, because the mean of its divisors is an integer number (17325).

2²¹⁷¹²⁸ is an apocalyptic number.

It is an amenable number.

217128 is an abundant number, since it is smaller than the sum of its proper divisors (337272).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217128 is a wasteful number, since it uses less digits than its factorization.

217128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201 (or 197 counting only the distinct ones).

The product of its digits is 224, while the sum is 21.

The square root of 217128 is about 465.9699561131. The cubic root of 217128 is about 60.1042631594.

The spelling of 217128 in words is "two hundred seventeen thousand, one hundred twenty-eight".