261361 has 4 divisors (see below), whose sum is σ = 269824. Its totient is φ = 252900.

The previous prime is 261353. The next prime is 261379. The reversal of 261361 is 163162.

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 261361 - 2³ = 261353 is a prime.

261361 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (261301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4185 + ... + 4246.

It is an arithmetic number, because the mean of its divisors is an integer number (67456).

2²⁶¹³⁶¹ is an apocalyptic number.

It is an amenable number.

261361 is a deficient number, since it is larger than the sum of its proper divisors (8463).

261361 is an equidigital number, since it uses as much as digits as its factorization.

261361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8462.

The product of its digits is 216, while the sum is 19.

The square root of 261361 is about 511.2347797245. The cubic root of 261361 is about 63.9362157488.

The spelling of 261361 in words is "two hundred sixty-one thousand, three hundred sixty-one".