822721 has 2 divisors, whose sum is σ = 822722. Its totient is φ = 822720.

The previous prime is 822713. The next prime is 822727. The reversal of 822721 is 127228.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 790321 + 32400 = 889^2 + 180^2 .

It is a cyclic number.

It is not a de Polignac number, because 822721 - 2³ = 822713 is a prime.

822721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 822692 and 822701.

It is not a weakly prime, because it can be changed into another prime (822727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411360 + 411361.

It is an arithmetic number, because the mean of its divisors is an integer number (411361).

2⁸²²⁷²¹ is an apocalyptic number.

It is an amenable number.

822721 is a deficient number, since it is larger than the sum of its proper divisors (1).

822721 is an equidigital number, since it uses as much as digits as its factorization.

822721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 448, while the sum is 22.

The square root of 822721 is about 907.0396904215. The cubic root of 822721 is about 93.7024315717.

Adding to 822721 its reverse (127228), we get a palindrome (949949).

The spelling of 822721 in words is "eight hundred twenty-two thousand, seven hundred twenty-one".