820243 has 2 divisors, whose sum is σ = 820244. Its totient is φ = 820242.

The previous prime is 820241. The next prime is 820247. The reversal of 820243 is 342028.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 820243 - 2¹ = 820241 is a prime.

Together with 820241, it forms a pair of twin primes.

820243 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 820243.

It is not a weakly prime, because it can be changed into another prime (820241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410121 + 410122.

It is an arithmetic number, because the mean of its divisors is an integer number (410122).

2⁸²⁰²⁴³ is an apocalyptic number.

820243 is a deficient number, since it is larger than the sum of its proper divisors (1).

820243 is an equidigital number, since it uses as much as digits as its factorization.

820243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 820243 is about 905.6726781790. The cubic root of 820243 is about 93.6082610747.

The spelling of 820243 in words is "eight hundred twenty thousand, two hundred forty-three".