261659 has 4 divisors (see below), whose sum is σ = 263016. Its totient is φ = 260304.

The previous prime is 261643. The next prime is 261673. The reversal of 261659 is 956162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261659 - 2⁴ = 261643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329 + ... + 794.

It is an arithmetic number, because the mean of its divisors is an integer number (65754).

2²⁶¹⁶⁵⁹ is an apocalyptic number.

261659 is a deficient number, since it is larger than the sum of its proper divisors (1357).

261659 is a wasteful number, since it uses less digits than its factorization.

It is an anagram of its base 11 representation: 261659 = (169652)₁₁.

261659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356.

The product of its digits is 3240, while the sum is 29.

The square root of 261659 is about 511.5261479143. The cubic root of 261659 is about 63.9605062328.

It can be divided in two parts, 26 and 1659, that multiplied together give a palindrome (43134).

The spelling of 261659 in words is "two hundred sixty-one thousand, six hundred fifty-nine".