1001809 has 2 divisors, whose sum is σ = 1001810. Its totient is φ = 1001808.

The previous prime is 1001807. The next prime is 1001821. The reversal of 1001809 is 9081001.

1001809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 861184 + 140625 = 928^2 + 375^2 .

It is an emirp because it is prime and its reverse (9081001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1001809 - 2¹ = 1001807 is a prime.

Together with 1001807, it forms a pair of twin primes.

1001809 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1001801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500904 + 500905.

It is an arithmetic number, because the mean of its divisors is an integer number (500905).

2^1001809 is an apocalyptic number.

It is an amenable number.

1001809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001809 is an equidigital number, since it uses as much as digits as its factorization.

1001809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 1001809 is about 1000.9040913095. The cubic root of 1001809 is about 100.0602636756.

The spelling of 1001809 in words is "one million, one thousand, eight hundred nine".