285620809 has 4 divisors (see below), whose sum is σ = 285662404. Its totient is φ = 285579216.

The previous prime is 285620779. The next prime is 285620851. The reversal of 285620809 is 908026582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 908026582 = 2 ⋅454013291.

It can be written as a sum of positive squares in 2 ways, for example, as 113486409 + 172134400 = 10653^2 + 13120^2 .

It is a cyclic number.

It is not a de Polignac number, because 285620809 - 2¹⁹ = 285096521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (285620899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7782 + ... + 25135.

It is an arithmetic number, because the mean of its divisors is an integer number (71415601).

Almost surely, 2^285620809 is an apocalyptic number.

It is an amenable number.

285620809 is a deficient number, since it is larger than the sum of its proper divisors (41595).

285620809 is an equidigital number, since it uses as much as digits as its factorization.

285620809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41594.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 285620809 is about 16900.3197898738. The cubic root of 285620809 is about 658.5619201010.

The spelling of 285620809 in words is "two hundred eighty-five million, six hundred twenty thousand, eight hundred nine".