169561 has 4 divisors (see below), whose sum is σ = 193792. Its totient is φ = 145332.

The previous prime is 169553. The next prime is 169567. The reversal of 169561 is 165961.

169561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 169561 - 2³ = 169553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (169567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12105 + ... + 12118.

It is an arithmetic number, because the mean of its divisors is an integer number (48448).

2¹⁶⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

169561 is a deficient number, since it is larger than the sum of its proper divisors (24231).

169561 is an equidigital number, since it uses as much as digits as its factorization.

169561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24230.

The product of its digits is 1620, while the sum is 28.

The square root of 169561 is about 411.7778527313. Note that the first 3 decimals coincide. The cubic root of 169561 is about 55.3488569532.

Subtracting from 169561 its reverse (165961), we obtain a square (3600 = 60²).

The spelling of 169561 in words is "one hundred sixty-nine thousand, five hundred sixty-one".