2820809 has 2 divisors, whose sum is σ = 2820810. Its totient is φ = 2820808.

The previous prime is 2820803. The next prime is 2820817. The reversal of 2820809 is 9080282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2550409 + 270400 = 1597^2 + 520^2 .

It is a cyclic number.

It is not a de Polignac number, because 2820809 - 2⁸ = 2820553 is a prime.

It is a plaindrome in base 15.

It is not a weakly prime, because it can be changed into another prime (2820803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1410404 + 1410405.

It is an arithmetic number, because the mean of its divisors is an integer number (1410405).

2^2820809 is an apocalyptic number.

It is an amenable number.

2820809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2820809 is an equidigital number, since it uses as much as digits as its factorization.

2820809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 2820809 is about 1679.5264213462. The cubic root of 2820809 is about 141.2942733275.

The spelling of 2820809 in words is "two million, eight hundred twenty thousand, eight hundred nine".