261955 has 4 divisors (see below), whose sum is σ = 314352. Its totient is φ = 209560.

The previous prime is 261917. The next prime is 261959. The reversal of 261955 is 559162.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 261955 - 2¹¹ = 259907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261959) 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, 26191 + ... + 26200.

It is an arithmetic number, because the mean of its divisors is an integer number (78588).

2²⁶¹⁹⁵⁵ is an apocalyptic number.

261955 is a deficient number, since it is larger than the sum of its proper divisors (52397).

261955 is an equidigital number, since it uses as much as digits as its factorization.

261955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52396.

The product of its digits is 2700, while the sum is 28.

The square root of 261955 is about 511.8153964077. The cubic root of 261955 is about 63.9846154427.

The spelling of 261955 in words is "two hundred sixty-one thousand, nine hundred fifty-five".