501665665 has 16 divisors (see below), whose sum is σ = 638122320. Its totient is φ = 377303040.

The previous prime is 501665663. The next prime is 501665701. The reversal of 501665665 is 566566105.

It can be written as a sum of positive squares in 8 ways, for example, as 1382976 + 500282689 = 1176^2 + 22367^2 .

It is not a de Polignac number, because 501665665 - 2¹ = 501665663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (501665663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88105 + ... + 93625.

It is an arithmetic number, because the mean of its divisors is an integer number (39882645).

Almost surely, 2^501665665 is an apocalyptic number.

It is an amenable number.

501665665 is a deficient number, since it is larger than the sum of its proper divisors (136456655).

501665665 is a wasteful number, since it uses less digits than its factorization.

501665665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6612.

The product of its (nonzero) digits is 162000, while the sum is 40.

The square root of 501665665 is about 22397.8942090546. The cubic root of 501665665 is about 794.5809085494.

The spelling of 501665665 in words is "five hundred one million, six hundred sixty-five thousand, six hundred sixty-five".