1665565 has 12 divisors (see below), whose sum is σ = 2197692. Its totient is φ = 1210880.

The previous prime is 1665563. The next prime is 1665569. The reversal of 1665565 is 5655661.

It can be written as a sum of positive squares in 2 ways, for example, as 1138489 + 527076 = 1067^2 + 726^2 .

It is not a de Polignac number, because 1665565 - 2¹ = 1665563 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1665565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665563) 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 11 ways as a sum of consecutive naturals, for example, 772 + ... + 1981.

It is an arithmetic number, because the mean of its divisors is an integer number (183141).

2^1665565 is an apocalyptic number.

It is an amenable number.

1665565 is a deficient number, since it is larger than the sum of its proper divisors (532127).

1665565 is a wasteful number, since it uses less digits than its factorization.

1665565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2780 (or 2769 counting only the distinct ones).

The product of its digits is 27000, while the sum is 34.

The square root of 1665565 is about 1290.5677045394. The cubic root of 1665565 is about 118.5369809864.

It can be divided in two parts, 1 and 665565, that added together give a palindrome (665566).

The spelling of 1665565 in words is "one million, six hundred sixty-five thousand, five hundred sixty-five".