9820 has 12 divisors (see below), whose sum is σ = 20664. Its totient is φ = 3920.

The previous prime is 9817. The next prime is 9829. The reversal of 9820 is 289.

9820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9829) 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, 226 + ... + 265.

It is an arithmetic number, because the mean of its divisors is an integer number (1722).

2⁹⁸²⁰ is an apocalyptic number.

It is an amenable number.

9820 is an abundant number, since it is smaller than the sum of its proper divisors (10844).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10332).

9820 is a wasteful number, since it uses less digits than its factorization.

9820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500 (or 498 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 9820 is about 99.0959131347. The cubic root of 9820 is about 21.4142973721.

Subtracting from 9820 its sum of digits (19), we obtain a square (9801 = 99²).

The spelling of 9820 in words is "nine thousand, eight hundred twenty".