1020809 has 4 divisors (see below), whose sum is σ = 1065216. Its totient is φ = 976404.

The previous prime is 1020797. The next prime is 1020821. The reversal of 1020809 is 9080201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1020797) and next prime (1020821).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1020809 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1020839) 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, 22169 + ... + 22214.

It is an arithmetic number, because the mean of its divisors is an integer number (266304).

2^1020809 is an apocalyptic number.

It is an amenable number.

1020809 is a deficient number, since it is larger than the sum of its proper divisors (44407).

1020809 is an equidigital number, since it uses as much as digits as its factorization.

1020809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44406.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 1020809 is about 1010.3509291330. The cubic root of 1020809 is about 100.6888769223.

The spelling of 1020809 in words is "one million, twenty thousand, eight hundred nine".