1801855 has 12 divisors (see below), whose sum is σ = 2371896. Its totient is φ = 1303200.

The previous prime is 1801853. The next prime is 1801867. The reversal of 1801855 is 5581081.

It is not a de Polignac number, because 1801855 - 2¹ = 1801853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9865 + ... + 10045.

It is an arithmetic number, because the mean of its divisors is an integer number (197658).

2^1801855 is an apocalyptic number.

1801855 is a deficient number, since it is larger than the sum of its proper divisors (570041).

1801855 is an equidigital number, since it uses as much as digits as its factorization.

1801855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 28.

The square root of 1801855 is about 1342.3319261643. The cubic root of 1801855 is about 121.6858125455.

The spelling of 1801855 in words is "one million, eight hundred one thousand, eight hundred fifty-five".