261807 has 24 divisors (see below), whose sum is σ = 440496. Its totient is φ = 137088.

The previous prime is 261799. The next prime is 261823. The reversal of 261807 is 708162.

It is not a de Polignac number, because 261807 - 2³ = 261799 is a prime.

It is a nialpdrome in base 13.

It is a zygodrome in base 4.

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 261807.

It is not an unprimeable number, because it can be changed into a prime (261847) 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, 1843 + ... + 1979.

It is an arithmetic number, because the mean of its divisors is an integer number (18354).

2²⁶¹⁸⁰⁷ is an apocalyptic number.

261807 is a deficient number, since it is larger than the sum of its proper divisors (178689).

261807 is a wasteful number, since it uses less digits than its factorization.

261807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 261807 is about 511.6707926001. The cubic root of 261807 is about 63.9725631092.

Adding to 261807 its reverse (708162), we get a palindrome (969969).

The spelling of 261807 in words is "two hundred sixty-one thousand, eight hundred seven".