1665006565 has 4 divisors (see below), whose sum is σ = 1998007884. Its totient is φ = 1332005248.

The previous prime is 1665006527. The next prime is 1665006599. The reversal of 1665006565 is 5656005661.

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 1055015361 + 609991204 = 32481^2 + 24698^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665006565 - 2⁷ = 1665006437 is a prime.

It is a super-2 number, since 2×1665006565² = 5544493722986198450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166500652 + ... + 166500661.

It is an arithmetic number, because the mean of its divisors is an integer number (499501971).

Almost surely, 2^1665006565 is an apocalyptic number.

It is an amenable number.

1665006565 is a deficient number, since it is larger than the sum of its proper divisors (333001319).

1665006565 is an equidigital number, since it uses as much as digits as its factorization.

1665006565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333001318.

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

The square root of 1665006565 is about 40804.4919708603. The cubic root of 1665006565 is about 1185.2373170898.

The spelling of 1665006565 in words is "one billion, six hundred sixty-five million, six thousand, five hundred sixty-five".