1809139 has 4 divisors (see below), whose sum is σ = 1851256. Its totient is φ = 1767024.

The previous prime is 1809133. The next prime is 1809149. The reversal of 1809139 is 9319081.

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

It is a cyclic number.

It is not a de Polignac number, because 1809139 - 2⁹ = 1808627 is a prime.

It is a Duffinian number.

1809139 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1809139.

It is not an unprimeable number, because it can be changed into a prime (1809133) 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, 20994 + ... + 21079.

It is an arithmetic number, because the mean of its divisors is an integer number (462814).

2^1809139 is an apocalyptic number.

1809139 is a deficient number, since it is larger than the sum of its proper divisors (42117).

1809139 is an equidigital number, since it uses as much as digits as its factorization.

1809139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42116.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 1809139 is about 1345.0423785145. The cubic root of 1809139 is about 121.8495637471.

The spelling of 1809139 in words is "one million, eight hundred nine thousand, one hundred thirty-nine".