261580 has 48 divisors (see below), whose sum is σ = 635040. Its totient is φ = 89600.

The previous prime is 261577. The next prime is 261581. The reversal of 261580 is 85162.

It is a happy number.

261580 is nontrivially palindromic in base 9.

It is a Harshad number since it is a multiple of its sum of digits (22).

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 15 ways as a sum of consecutive naturals, for example, 6360 + ... + 6400.

It is an arithmetic number, because the mean of its divisors is an integer number (13230).

2²⁶¹⁵⁸⁰ is an apocalyptic number.

261580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (317520).

261580 is an abundant number, since it is smaller than the sum of its proper divisors (373460).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261580 is a wasteful number, since it uses less digits than its factorization.

261580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 261580 is about 511.4489221809. The cubic root of 261580 is about 63.9540686064.

It can be divided in two parts, 261 and 580, that added together give a square (841 = 29²).

The spelling of 261580 in words is "two hundred sixty-one thousand, five hundred eighty".