821216 has 24 divisors (see below), whose sum is σ = 1764504. Its totient is φ = 373120.

The previous prime is 821209. The next prime is 821263. The reversal of 821216 is 612128.

It is a congruent number.

It is an unprimeable number.

821216 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815 + ... + 1518.

It is an arithmetic number, because the mean of its divisors is an integer number (73521).

2⁸²¹²¹⁶ is an apocalyptic number.

It is an amenable number.

821216 is an abundant number, since it is smaller than the sum of its proper divisors (943288).

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

821216 is a wasteful number, since it uses less digits than its factorization.

821216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2354 (or 2346 counting only the distinct ones).

The product of its digits is 192, while the sum is 20.

The square root of 821216 is about 906.2096887586. The cubic root of 821216 is about 93.6452602109.

It can be divided in two parts, 8212 and 16, that added together give a palindrome (8228).

The spelling of 821216 in words is "eight hundred twenty-one thousand, two hundred sixteen".