217868 has 24 divisors (see below), whose sum is σ = 451584. Its totient is φ = 90000.

The previous prime is 217859. The next prime is 217901. The reversal of 217868 is 868712.

217868 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 743 + ... + 993.

It is an arithmetic number, because the mean of its divisors is an integer number (18816).

2²¹⁷⁸⁶⁸ is an apocalyptic number.

217868 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (225792).

217868 is an abundant number, since it is smaller than the sum of its proper divisors (233716).

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

217868 is a wasteful number, since it uses less digits than its factorization.

217868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 291 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 217868 is about 466.7633233235. The cubic root of 217868 is about 60.1724667417.

It can be divided in two parts, 217 and 868, that multiplied together give a square (188356 = 434²).

The spelling of 217868 in words is "two hundred seventeen thousand, eight hundred sixty-eight".