165664565 has 16 divisors (see below), whose sum is σ = 218534976. Its totient is φ = 119558400.

The previous prime is 165664547. The next prime is 165664567. The reversal of 165664565 is 565466561.

It is a happy number.

It is not a de Polignac number, because 165664565 - 2¹⁶ = 165599029 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165664567) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 4292 + ... + 18701.

It is an arithmetic number, because the mean of its divisors is an integer number (13658436).

Almost surely, 2^165664565 is an apocalyptic number.

It is an amenable number.

165664565 is a deficient number, since it is larger than the sum of its proper divisors (52870411).

165664565 is a wasteful number, since it uses less digits than its factorization.

165664565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23140.

The product of its digits is 648000, while the sum is 44.

The square root of 165664565 is about 12871.0747414503. The cubic root of 165664565 is about 549.2160345883.

The spelling of 165664565 in words is "one hundred sixty-five million, six hundred sixty-four thousand, five hundred sixty-five".