1665865 has 8 divisors (see below), whose sum is σ = 2033280. Its totient is φ = 1309872.

The previous prime is 1665841. The next prime is 1665869. The reversal of 1665865 is 5685661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1665865 - 2¹³ = 1657673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1665869) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2529 + ... + 3118.

It is an arithmetic number, because the mean of its divisors is an integer number (254160).

2^1665865 is an apocalyptic number.

It is an amenable number.

1665865 is a deficient number, since it is larger than the sum of its proper divisors (367415).

1665865 is an equidigital number, since it uses as much as digits as its factorization.

1665865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5711.

The product of its digits is 43200, while the sum is 37.

The square root of 1665865 is about 1290.6839272262. The cubic root of 1665865 is about 118.5440974823.

The spelling of 1665865 in words is "one million, six hundred sixty-five thousand, eight hundred sixty-five".