820609 has 2 divisors, whose sum is σ = 820610. Its totient is φ = 820608.

The previous prime is 820597. The next prime is 820619. The reversal of 820609 is 906028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 810000 + 10609 = 900^2 + 103^2 .

It is a cyclic number.

It is not a de Polignac number, because 820609 - 2⁵ = 820577 is a prime.

It is not a weakly prime, because it can be changed into another prime (820619) 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, 410304 + 410305.

It is an arithmetic number, because the mean of its divisors is an integer number (410305).

2⁸²⁰⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

820609 is a deficient number, since it is larger than the sum of its proper divisors (1).

820609 is an equidigital number, since it uses as much as digits as its factorization.

820609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 820609 is about 905.8747153994. The cubic root of 820609 is about 93.6221819612.

The spelling of 820609 in words is "eight hundred twenty thousand, six hundred nine".