217830 has 32 divisors (see below), whose sum is σ = 536544. Its totient is φ = 56576.

The previous prime is 217829. The next prime is 217849. The reversal of 217830 is 38712.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 217797 and 217806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1522 + ... + 1658.

It is an arithmetic number, because the mean of its divisors is an integer number (16767).

2²¹⁷⁸³⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (268272).

217830 is an abundant number, since it is smaller than the sum of its proper divisors (318714).

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

217830 is a wasteful number, since it uses less digits than its factorization.

217830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 217830 is about 466.7226156937. The cubic root of 217830 is about 60.1689681604.

The spelling of 217830 in words is "two hundred seventeen thousand, eight hundred thirty".