217992 has 32 divisors (see below), whose sum is σ = 564480. Its totient is φ = 70080.

The previous prime is 217981. The next prime is 218003. The reversal of 217992 is 299712.

217992 is nontrivially palindromic in base 5.

It is an interprime number because it is at equal distance from previous prime (217981) and next prime (218003).

It is a plaindrome in base 15.

It is an unprimeable number.

217992 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, 598 + ... + 890.

It is an arithmetic number, because the mean of its divisors is an integer number (17640).

2²¹⁷⁹⁹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (282240).

217992 is an abundant number, since it is smaller than the sum of its proper divisors (346488).

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

217992 is a wasteful number, since it uses less digits than its factorization.

217992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333 (or 329 counting only the distinct ones).

The product of its digits is 2268, while the sum is 30.

The square root of 217992 is about 466.8961340598. The cubic root of 217992 is about 60.1838803358.

The spelling of 217992 in words is "two hundred seventeen thousand, nine hundred ninety-two".