1820563 has 6 divisors (see below), whose sum is σ = 1855484. Its totient is φ = 1786284.

The previous prime is 1820557. The next prime is 1820573. The reversal of 1820563 is 3650281.

It is a happy number.

It is not a de Polignac number, because 1820563 - 2⁹ = 1820051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3220 + ... + 3742.

2^1820563 is an apocalyptic number.

1820563 is a deficient number, since it is larger than the sum of its proper divisors (34921).

1820563 is an frugal number, since it uses more digits than its factorization.

1820563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641 (or 582 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1820563 is about 1349.2824018715. The cubic root of 1820563 is about 122.1055031110.

The spelling of 1820563 in words is "one million, eight hundred twenty thousand, five hundred sixty-three".