1665505 has 4 divisors (see below), whose sum is σ = 1998612. Its totient is φ = 1332400.

The previous prime is 1665493. The next prime is 1665523. The reversal of 1665505 is 5055661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5055661 = 13 ⋅388897.

It can be written as a sum of positive squares in 2 ways, for example, as 501264 + 1164241 = 708^2 + 1079^2 .

It is not a de Polignac number, because 1665505 - 2¹¹ = 1663457 is a prime.

It is a Duffinian 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, 166546 + ... + 166555.

It is an arithmetic number, because the mean of its divisors is an integer number (499653).

2^1665505 is an apocalyptic number.

It is an amenable number.

1665505 is a deficient number, since it is larger than the sum of its proper divisors (333107).

1665505 is an equidigital number, since it uses as much as digits as its factorization.

1665505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333106.

The product of its (nonzero) digits is 4500, while the sum is 28.

The square root of 1665505 is about 1290.5444587460. The cubic root of 1665505 is about 118.5355575847.

It can be divided in two parts, 166 and 5505, that added together give a triangular number (5671 = T₁₀₆).

The spelling of 1665505 in words is "one million, six hundred sixty-five thousand, five hundred five".