501665 has 4 divisors (see below), whose sum is σ = 602004. Its totient is φ = 401328.

The previous prime is 501659. The next prime is 501691. The reversal of 501665 is 566105.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 287296 + 214369 = 536^2 + 463^2 .

It is a cyclic number.

It is not a de Polignac number, because 501665 - 2⁶ = 501601 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 501665.

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, 50162 + ... + 50171.

It is an arithmetic number, because the mean of its divisors is an integer number (150501).

2⁵⁰¹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

501665 is a deficient number, since it is larger than the sum of its proper divisors (100339).

501665 is a wasteful number, since it uses less digits than its factorization.

501665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100338.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 501665 is about 708.2831354762. The cubic root of 501665 is about 79.4580557455.

The spelling of 501665 in words is "five hundred one thousand, six hundred sixty-five".