217123 has 4 divisors (see below), whose sum is σ = 224640. Its totient is φ = 209608.

The previous prime is 217121. The next prime is 217157. The reversal of 217123 is 321712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 217123 - 2¹ = 217121 is a prime.

It is a Duffinian number.

217123 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 217097 and 217106.

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, 3715 + ... + 3772.

It is an arithmetic number, because the mean of its divisors is an integer number (56160).

2²¹⁷¹²³ is an apocalyptic number.

217123 is a deficient number, since it is larger than the sum of its proper divisors (7517).

217123 is an equidigital number, since it uses as much as digits as its factorization.

217123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7516.

The product of its digits is 84, while the sum is 16.

The square root of 217123 is about 465.9645909294. The cubic root of 217123 is about 60.1038017977.

Adding to 217123 its reverse (321712), we get a palindrome (538835).

The spelling of 217123 in words is "two hundred seventeen thousand, one hundred twenty-three", and thus it is an iban number.