1802009 has 4 divisors (see below), whose sum is σ = 1965840. Its totient is φ = 1638180.

The previous prime is 1801997. The next prime is 1802029. The reversal of 1802009 is 9002081.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9002081 = 11 ⋅818371.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1802009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (1802029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81899 + ... + 81920.

It is an arithmetic number, because the mean of its divisors is an integer number (491460).

2^1802009 is an apocalyptic number.

It is an amenable number.

1802009 is a deficient number, since it is larger than the sum of its proper divisors (163831).

1802009 is a wasteful number, since it uses less digits than its factorization.

1802009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163830.

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

The square root of 1802009 is about 1342.3892877999. The cubic root of 1802009 is about 121.6892791731.

The spelling of 1802009 in words is "one million, eight hundred two thousand, nine".