165665531 has 8 divisors (see below), whose sum is σ = 167437824. Its totient is φ = 163900800.

The previous prime is 165665483. The next prime is 165665537. The reversal of 165665531 is 135566561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165665531 - 2¹⁴ = 165649147 is a prime.

It is a super-2 number, since 2×165665531² = 54890136323023922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165665537) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49301 + ... + 52553.

It is an arithmetic number, because the mean of its divisors is an integer number (20929728).

Almost surely, 2^165665531 is an apocalyptic number.

165665531 is a deficient number, since it is larger than the sum of its proper divisors (1772293).

165665531 is a wasteful number, since it uses less digits than its factorization.

165665531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3781.

The product of its digits is 81000, while the sum is 38.

The square root of 165665531 is about 12871.1122673994. The cubic root of 165665531 is about 549.2171020901.

The spelling of 165665531 in words is "one hundred sixty-five million, six hundred sixty-five thousand, five hundred thirty-one".