217828 has 24 divisors (see below), whose sum is σ = 423360. Its totient is φ = 97440.

The previous prime is 217823. The next prime is 217829. The reversal of 217828 is 828712.

217828 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 217796 and 217805.

It is not an unprimeable number, because it can be changed into a prime (217823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3033 + ... + 3103.

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

2²¹⁷⁸²⁸ is an apocalyptic number.

It is an amenable number.

217828 is a deficient number, since it is larger than the sum of its proper divisors (205532).

217828 is a wasteful number, since it uses less digits than its factorization.

217828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147 (or 145 counting only the distinct ones).

The product of its digits is 1792, while the sum is 28.

The square root of 217828 is about 466.7204730886. The cubic root of 217828 is about 60.1687840133.

The spelling of 217828 in words is "two hundred seventeen thousand, eight hundred twenty-eight".