821120 has 32 divisors (see below), whose sum is σ = 1964520. Its totient is φ = 328192.

The previous prime is 821113. The next prime is 821131. The reversal of 821120 is 21128.

It is a tau number, because it is divible by the number of its divisors (32).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 821095 and 821104.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 821120.

It is an unprimeable number.

821120 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 2 + ... + 1281.

2⁸²¹¹²⁰ is an apocalyptic number.

821120 is a gapful number since it is divisible by the number (80) 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 821120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (982260).

821120 is an abundant number, since it is smaller than the sum of its proper divisors (1143400).

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

821120 is a wasteful number, since it uses less digits than its factorization.

821120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1302 (or 1290 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 821120 is about 906.1567193372. The cubic root of 821120 is about 93.6416110308.

Adding to 821120 its reverse (21128), we get a palindrome (842248).

The spelling of 821120 in words is "eight hundred twenty-one thousand, one hundred twenty".