1666565 has 8 divisors (see below), whose sum is σ = 2014200. Its totient is φ = 1323712.

The previous prime is 1666559. The next prime is 1666589. The reversal of 1666565 is 5656661.

It can be written as a sum of positive squares in 4 ways, for example, as 111556 + 1555009 = 334^2 + 1247^2 .

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 1666565 - 2⁸ = 1666309 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 374 + ... + 1863.

It is an arithmetic number, because the mean of its divisors is an integer number (251775).

2^1666565 is an apocalyptic number.

It is an amenable number.

1666565 is a deficient number, since it is larger than the sum of its proper divisors (347635).

1666565 is a wasteful number, since it uses less digits than its factorization.

1666565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2391.

The product of its digits is 32400, while the sum is 35.

The square root of 1666565 is about 1290.9550728046. The cubic root of 1666565 is about 118.5606993174.

It can be divided in two parts, 166656 and 5, that added together give a palindrome (166661).

The spelling of 1666565 in words is "one million, six hundred sixty-six thousand, five hundred sixty-five".