161305 has 4 divisors (see below), whose sum is σ = 193572. Its totient is φ = 129040.

The previous prime is 161303. The next prime is 161309. The reversal of 161305 is 503161.

161305 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 an emirpimes, since its reverse is a distinct semiprime: 503161 = 31 ⋅16231.

It can be written as a sum of positive squares in 2 ways, for example, as 33856 + 127449 = 184^2 + 357^2 .

It is not a de Polignac number, because 161305 - 2¹ = 161303 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161303) 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, 16126 + ... + 16135.

It is an arithmetic number, because the mean of its divisors is an integer number (48393).

2¹⁶¹³⁰⁵ is an apocalyptic number.

It is an amenable number.

161305 is a deficient number, since it is larger than the sum of its proper divisors (32267).

161305 is an equidigital number, since it uses as much as digits as its factorization.

161305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32266.

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 161305 is about 401.6279372753. The cubic root of 161305 is about 54.4355493204.

Adding to 161305 its reverse (503161), we get a palindrome (664466).

The spelling of 161305 in words is "one hundred sixty-one thousand, three hundred five".