1820805 has 16 divisors (see below), whose sum is σ = 3329664. Its totient is φ = 832320.

The previous prime is 1820783. The next prime is 1820809. The reversal of 1820805 is 5080281.

It is not a de Polignac number, because 1820805 - 2⁵ = 1820773 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820809) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8566 + ... + 8775.

It is an arithmetic number, because the mean of its divisors is an integer number (208104).

2^1820805 is an apocalyptic number.

1820805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1820805 is a deficient number, since it is larger than the sum of its proper divisors (1508859).

1820805 is a wasteful number, since it uses less digits than its factorization.

1820805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17356.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 1820805 is about 1349.3720761895. The cubic root of 1820805 is about 122.1109131998.

The spelling of 1820805 in words is "one million, eight hundred twenty thousand, eight hundred five".