820399 has 2 divisors, whose sum is σ = 820400. Its totient is φ = 820398.

The previous prime is 820367. The next prime is 820409. The reversal of 820399 is 993028.

It is a happy number.

820399 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 820399 - 2⁵ = 820367 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 820399.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410199 + 410200.

It is an arithmetic number, because the mean of its divisors is an integer number (410200).

2⁸²⁰³⁹⁹ is an apocalyptic number.

820399 is a deficient number, since it is larger than the sum of its proper divisors (1).

820399 is an equidigital number, since it uses as much as digits as its factorization.

820399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 820399 is about 905.7587979148. The cubic root of 820399 is about 93.6141950736.

The spelling of 820399 in words is "eight hundred twenty thousand, three hundred ninety-nine".