821872 has 20 divisors (see below), whose sum is σ = 1644736. Its totient is φ = 397440.

The previous prime is 821869. The next prime is 821879. The reversal of 821872 is 278128.

821872 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 821872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 333 + ... + 1324.

2⁸²¹⁸⁷² is an apocalyptic number.

It is an amenable number.

821872 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

821872 is a wasteful number, since it uses less digits than its factorization.

821872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1696 (or 1690 counting only the distinct ones).

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

The square root of 821872 is about 906.5715636396. The cubic root of 821872 is about 93.6701886668.

The spelling of 821872 in words is "eight hundred twenty-one thousand, eight hundred seventy-two".