821992 has 16 divisors (see below), whose sum is σ = 1583460. Its totient is φ = 399744.

The previous prime is 821971. The next prime is 821993. The reversal of 821992 is 299128.

It can be written as a sum of positive squares in 2 ways, for example, as 820836 + 1156 = 906^2 + 34^2 .

It is not an unprimeable number, because it can be changed into a prime (821993) 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, 1093 + ... + 1684.

2⁸²¹⁹⁹² is an apocalyptic number.

It is an amenable number.

821992 is a deficient number, since it is larger than the sum of its proper divisors (761468).

821992 is a wasteful number, since it uses less digits than its factorization.

821992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2820 (or 2816 counting only the distinct ones).

The product of its digits is 2592, while the sum is 31.

The square root of 821992 is about 906.6377446367. The cubic root of 821992 is about 93.6747473149.

The spelling of 821992 in words is "eight hundred twenty-one thousand, nine hundred ninety-two".