1818865 has 4 divisors (see below), whose sum is σ = 2182644. Its totient is φ = 1455088.

The previous prime is 1818833. The next prime is 1818871. The reversal of 1818865 is 5688181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5688181 = 257 ⋅22133.

It can be written as a sum of positive squares in 2 ways, for example, as 1361889 + 456976 = 1167^2 + 676^2 .

It is a cyclic number.

It is not a de Polignac number, because 1818865 - 2⁵ = 1818833 is a prime.

It is a Duffinian number.

1818865 is a lucky number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181882 + ... + 181891.

It is an arithmetic number, because the mean of its divisors is an integer number (545661).

2^1818865 is an apocalyptic number.

It is an amenable number.

1818865 is a deficient number, since it is larger than the sum of its proper divisors (363779).

1818865 is an equidigital number, since it uses as much as digits as its factorization.

1818865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363778.

The product of its digits is 15360, while the sum is 37.

The square root of 1818865 is about 1348.6530317320. The cubic root of 1818865 is about 122.0675295763.

The spelling of 1818865 in words is "one million, eight hundred eighteen thousand, eight hundred sixty-five".