1816909 has 4 divisors (see below), whose sum is σ = 1923804. Its totient is φ = 1710016.

The previous prime is 1816901. The next prime is 1816933. The reversal of 1816909 is 9096181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1357225 + 459684 = 1165^2 + 678^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816909 - 2³ = 1816901 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

1816909 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816901) 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 3 ways as a sum of consecutive naturals, for example, 53422 + ... + 53455.

It is an arithmetic number, because the mean of its divisors is an integer number (480951).

2^1816909 is an apocalyptic number.

It is an amenable number.

1816909 is a deficient number, since it is larger than the sum of its proper divisors (106895).

1816909 is a wasteful number, since it uses less digits than its factorization.

1816909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106894.

The product of its (nonzero) digits is 3888, while the sum is 34.

The square root of 1816909 is about 1347.9276686826. The cubic root of 1816909 is about 122.0237569072.

The spelling of 1816909 in words is "one million, eight hundred sixteen thousand, nine hundred nine".