1800845 has 4 divisors (see below), whose sum is σ = 2161020. Its totient is φ = 1440672.

The previous prime is 1800833. The next prime is 1800853. The reversal of 1800845 is 5480081.

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 1408969 + 391876 = 1187^2 + 626^2 .

It is a cyclic number.

It is not a de Polignac number, because 1800845 - 2⁴ = 1800829 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 180080 + ... + 180089.

It is an arithmetic number, because the mean of its divisors is an integer number (540255).

2^1800845 is an apocalyptic number.

It is an amenable number.

1800845 is a deficient number, since it is larger than the sum of its proper divisors (360175).

1800845 is an equidigital number, since it uses as much as digits as its factorization.

1800845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360174.

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 1800845 is about 1341.9556624568. The cubic root of 1800845 is about 121.6630719732.

The spelling of 1800845 in words is "one million, eight hundred thousand, eight hundred forty-five".