217129 has 4 divisors (see below), whose sum is σ = 236880. Its totient is φ = 197380.

The previous prime is 217121. The next prime is 217157. The reversal of 217129 is 921712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 217129 - 2³ = 217121 is a prime.

It is a Duffinian number.

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

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9859 + ... + 9880.

It is an arithmetic number, because the mean of its divisors is an integer number (59220).

2²¹⁷¹²⁹ is an apocalyptic number.

It is an amenable number.

217129 is a deficient number, since it is larger than the sum of its proper divisors (19751).

217129 is a wasteful number, since it uses less digits than its factorization.

217129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19750.

The product of its digits is 252, while the sum is 22.

The square root of 217129 is about 465.9710291424. The cubic root of 217129 is about 60.1043554309.

The spelling of 217129 in words is "two hundred seventeen thousand, one hundred twenty-nine".