165000561 has 12 divisors (see below), whose sum is σ = 241819536. Its totient is φ = 100000120.

The previous prime is 165000553. The next prime is 165000593.

165000561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 165000561 - 2³ = 165000553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (165000461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 226911 + ... + 227636.

It is an arithmetic number, because the mean of its divisors is an integer number (20151628).

Almost surely, 2^165000561 is an apocalyptic number.

165000561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165000561 is a deficient number, since it is larger than the sum of its proper divisors (76818975).

165000561 is a wasteful number, since it uses less digits than its factorization.

165000561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454572 (or 454561 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 165000561 is about 12845.2544155420. The cubic root of 165000561 is about 548.4812768540.

It can be divided in two parts, 165000 and 561, that added together give a palindrome (165561).

The spelling of 165000561 in words is "one hundred sixty-five million, five hundred sixty-one", and thus it is an aban number.