261749 has 8 divisors (see below), whose sum is σ = 281880. Its totient is φ = 242176.

The previous prime is 261739. The next prime is 261757. The reversal of 261749 is 947162.

It can be written as a sum of positive squares in 4 ways, for example, as 87025 + 174724 = 295^2 + 418^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1427 + ... + 1599.

It is an arithmetic number, because the mean of its divisors is an integer number (35235).

2²⁶¹⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

261749 is a deficient number, since it is larger than the sum of its proper divisors (20131).

261749 is a wasteful number, since it uses less digits than its factorization.

It is an anagram of its base 11 representation: 261749 = (169724)₁₁.

261749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279.

The product of its digits is 3024, while the sum is 29.

The square root of 261749 is about 511.6141123933. The cubic root of 261749 is about 63.9678386587.

The spelling of 261749 in words is "two hundred sixty-one thousand, seven hundred forty-nine".