822821 has 2 divisors, whose sum is σ = 822822. Its totient is φ = 822820.

The previous prime is 822803. The next prime is 822823. The reversal of 822821 is 128228.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 474721 + 348100 = 689^2 + 590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-822821 is a prime.

It is a Sophie Germain prime.

Together with 822823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (822823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411410 + 411411.

It is an arithmetic number, because the mean of its divisors is an integer number (411411).

2⁸²²⁸²¹ is an apocalyptic number.

It is an amenable number.

822821 is a deficient number, since it is larger than the sum of its proper divisors (1).

822821 is an equidigital number, since it uses as much as digits as its factorization.

822821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 512, while the sum is 23.

The square root of 822821 is about 907.0948131259. The cubic root of 822821 is about 93.7062278621.

The spelling of 822821 in words is "eight hundred twenty-two thousand, eight hundred twenty-one".