165259661 has 16 divisors (see below), whose sum is σ = 199549440. Its totient is φ = 133848960.

The previous prime is 165259651. The next prime is 165259687. The reversal of 165259661 is 166952561.

It is not a de Polignac number, because 165259661 - 2¹⁴ = 165243277 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165259651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 881 + ... + 18201.

It is an arithmetic number, because the mean of its divisors is an integer number (12471840).

Almost surely, 2^165259661 is an apocalyptic number.

It is an amenable number.

165259661 is a deficient number, since it is larger than the sum of its proper divisors (34289779).

165259661 is a wasteful number, since it uses less digits than its factorization.

165259661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17404.

The product of its digits is 97200, while the sum is 41.

The square root of 165259661 is about 12855.3358960394. The cubic root of 165259661 is about 548.7682196720.

The spelling of 165259661 in words is "one hundred sixty-five million, two hundred fifty-nine thousand, six hundred sixty-one".