217109 has 4 divisors (see below), whose sum is σ = 218400. Its totient is φ = 215820.

The previous prime is 217081. The next prime is 217111. The reversal of 217109 is 901712.

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 217109 - 2¹⁶ = 151573 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217169) 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, 347 + ... + 744.

It is an arithmetic number, because the mean of its divisors is an integer number (54600).

2²¹⁷¹⁰⁹ is an apocalyptic number.

It is an amenable number.

217109 is a deficient number, since it is larger than the sum of its proper divisors (1291).

217109 is a wasteful number, since it uses less digits than its factorization.

217109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1290.

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 217109 is about 465.9495680865. The cubic root of 217109 is about 60.1025099473.

It can be divided in two parts, 217 and 109, that multiplied together give a triangular number (23653 = T₂₁₇).

The spelling of 217109 in words is "two hundred seventeen thousand, one hundred nine".