165693561 has 16 divisors (see below), whose sum is σ = 242551488. Its totient is φ = 99777600.

The previous prime is 165693553. The next prime is 165693571. The reversal of 165693561 is 165396561.

It is not a de Polignac number, because 165693561 - 2³ = 165693553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165693571) 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, 10810 + ... + 21171.

It is an arithmetic number, because the mean of its divisors is an integer number (15159468).

Almost surely, 2^165693561 is an apocalyptic number.

165693561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165693561 is a deficient number, since it is larger than the sum of its proper divisors (76857927).

165693561 is a wasteful number, since it uses less digits than its factorization.

165693561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32152.

The product of its digits is 145800, while the sum is 42.

The square root of 165693561 is about 12872.2010938301. The cubic root of 165693561 is about 549.2480755162.

The spelling of 165693561 in words is "one hundred sixty-five million, six hundred ninety-three thousand, five hundred sixty-one".