1605006565 has 4 divisors (see below), whose sum is σ = 1926007884. Its totient is φ = 1284005248.

The previous prime is 1605006547. The next prime is 1605006577. The reversal of 1605006565 is 5656005061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5656005061 = 7 ⋅808000723.

It can be written as a sum of positive squares in 2 ways, for example, as 779191396 + 825815169 = 27914^2 + 28737^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1605006565 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 1605006565.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160500652 + ... + 160500661.

It is an arithmetic number, because the mean of its divisors is an integer number (481501971).

Almost surely, 2^1605006565 is an apocalyptic number.

It is an amenable number.

1605006565 is a deficient number, since it is larger than the sum of its proper divisors (321001319).

1605006565 is an equidigital number, since it uses as much as digits as its factorization.

1605006565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321001318.

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 1605006565 is about 40062.5331825136. The cubic root of 1605006565 is about 1170.8257654584.

The spelling of 1605006565 in words is "one billion, six hundred five million, six thousand, five hundred sixty-five".