161109 has 28 divisors (see below), whose sum is σ = 275436. Its totient is φ = 93312.

The previous prime is 161093. The next prime is 161123. The reversal of 161109 is 901161.

It can be written as a sum of positive squares in 2 ways, for example, as 72900 + 88209 = 270^2 + 297^2 .

It is not a de Polignac number, because 161109 - 2⁴ = 161093 is a prime.

It is a super-2 number, since 2×161109² = 51912219762, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161091 and 161100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161149) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 9469 + ... + 9485.

It is an arithmetic number, because the mean of its divisors is an integer number (9837).

2¹⁶¹¹⁰⁹ is an apocalyptic number.

It is an amenable number.

161109 is a deficient number, since it is larger than the sum of its proper divisors (114327).

161109 is an equidigital number, since it uses as much as digits as its factorization.

161109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48 (or 33 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 18.

The square root of 161109 is about 401.3838561776. The cubic root of 161109 is about 54.4134923641.

The spelling of 161109 in words is "one hundred sixty-one thousand, one hundred nine".