261583 has 4 divisors (see below), whose sum is σ = 298960. Its totient is φ = 224208.

The previous prime is 261581. The next prime is 261587. The reversal of 261583 is 385162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 385162 = 2 ⋅192581.

It is a cyclic number.

It is not a de Polignac number, because 261583 - 2¹ = 261581 is a prime.

It is a Duffinian number.

261583 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261581) 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, 18678 + ... + 18691.

It is an arithmetic number, because the mean of its divisors is an integer number (74740).

261583 is a Friedman number, since it can be written as 8^(3*2)-561, using all its digits and the basic arithmetic operations.

2²⁶¹⁵⁸³ is an apocalyptic number.

261583 is a deficient number, since it is larger than the sum of its proper divisors (37377).

261583 is an equidigital number, since it uses as much as digits as its factorization.

261583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37376.

The product of its digits is 1440, while the sum is 25.

The square root of 261583 is about 511.4518550167. The cubic root of 261583 is about 63.9543130969.

The spelling of 261583 in words is "two hundred sixty-one thousand, five hundred eighty-three".