249561 has 24 divisors (see below), whose sum is σ = 407680. Its totient is φ = 151632.

The previous prime is 249541. The next prime is 249563. The reversal of 249561 is 165942.

It is not a de Polignac number, because 249561 - 2⁶ = 249497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 249561.

It is not an unprimeable number, because it can be changed into a prime (249563) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3120 + ... + 3198.

249561 is a Friedman number, since it can be written as 9^(4-1)+(6*2)^5, using all its digits and the basic arithmetic operations.

2²⁴⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

249561 is a deficient number, since it is larger than the sum of its proper divisors (158119).

249561 is an equidigital number, since it uses as much as digits as its factorization.

249561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 95 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 249561 is about 499.5608071096. The cubic root of 249561 is about 62.9591572009.

It can be divided in two parts, 2495 and 61, that added together give a triangular number (2556 = T₇₁).

The spelling of 249561 in words is "two hundred forty-nine thousand, five hundred sixty-one".