261586 has 8 divisors (see below), whose sum is σ = 422604. Its totient is φ = 120720.

The previous prime is 261581. The next prime is 261587. The reversal of 261586 is 685162.

It can be written as a sum of positive squares in 2 ways, for example, as 255025 + 6561 = 505^2 + 81^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (261581) 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, 5005 + ... + 5056.

2²⁶¹⁵⁸⁶ is an apocalyptic number.

261586 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

261586 is a deficient number, since it is larger than the sum of its proper divisors (161018).

261586 is a wasteful number, since it uses less digits than its factorization.

261586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10076.

The product of its digits is 2880, while the sum is 28.

The square root of 261586 is about 511.4547878356. The cubic root of 261586 is about 63.9545575856.

It can be divided in two parts, 2615 and 86, that added together give a triangular number (2701 = T₇₃).

The spelling of 261586 in words is "two hundred sixty-one thousand, five hundred eighty-six".