261249 has 4 divisors (see below), whose sum is σ = 348336. Its totient is φ = 174164.

The previous prime is 261241. The next prime is 261251. The reversal of 261249 is 942162.

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 261249 - 2³ = 261241 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (261241) 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, 43539 + ... + 43544.

It is an arithmetic number, because the mean of its divisors is an integer number (87084).

2²⁶¹²⁴⁹ is an apocalyptic number.

It is an amenable number.

261249 is a deficient number, since it is larger than the sum of its proper divisors (87087).

261249 is an equidigital number, since it uses as much as digits as its factorization.

261249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87086.

The product of its digits is 864, while the sum is 24.

The square root of 261249 is about 511.1252292736. The cubic root of 261249 is about 63.9270816657.

It can be divided in two parts, 26 and 1249, that added together give a triangular number (1275 = T₅₀).

The spelling of 261249 in words is "two hundred sixty-one thousand, two hundred forty-nine".