1806865 has 4 divisors (see below), whose sum is σ = 2168244. Its totient is φ = 1445488.

The previous prime is 1806863. The next prime is 1806869. The reversal of 1806865 is 5686081.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5686081 = 83 ⋅68507.

It can be written as a sum of positive squares in 2 ways, for example, as 620944 + 1185921 = 788^2 + 1089^2 .

It is a cyclic number.

It is not a de Polignac number, because 1806865 - 2¹ = 1806863 is a prime.

It is a super-2 number, since 2×1806865² = 6529522256450, which contains 22 as substring.

It is a Duffinian number.

1806865 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1806865.

It is not an unprimeable number, because it can be changed into a prime (1806863) 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, 180682 + ... + 180691.

It is an arithmetic number, because the mean of its divisors is an integer number (542061).

2^1806865 is an apocalyptic number.

It is an amenable number.

1806865 is a deficient number, since it is larger than the sum of its proper divisors (361379).

1806865 is an equidigital number, since it uses as much as digits as its factorization.

1806865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361378.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 1806865 is about 1344.1967861887. The cubic root of 1806865 is about 121.7984893440.

The spelling of 1806865 in words is "one million, eight hundred six thousand, eight hundred sixty-five".