261109 has 4 divisors (see below), whose sum is σ = 268204. Its totient is φ = 254016.

The previous prime is 261101. The next prime is 261127. The reversal of 261109 is 901162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 901162 = 2 ⋅450581.

It can be written as a sum of positive squares in 2 ways, for example, as 253009 + 8100 = 503^2 + 90^2 .

It is a cyclic number.

It is not a de Polignac number, because 261109 - 2³ = 261101 is a prime.

It is a Duffinian number.

261109 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261101) 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, 3492 + ... + 3565.

It is an arithmetic number, because the mean of its divisors is an integer number (67051).

2²⁶¹¹⁰⁹ is an apocalyptic number.

It is an amenable number.

261109 is a deficient number, since it is larger than the sum of its proper divisors (7095).

261109 is an equidigital number, since it uses as much as digits as its factorization.

261109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7094.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 261109 is about 510.9882581821. The cubic root of 261109 is about 63.9156603899.

The spelling of 261109 in words is "two hundred sixty-one thousand, one hundred nine".