261859 has 4 divisors (see below), whose sum is σ = 282016. Its totient is φ = 241704.

The previous prime is 261847. The next prime is 261881. The reversal of 261859 is 958162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 958162 = 2 ⋅479081.

It is a cyclic number.

It is not a de Polignac number, because 261859 - 2⁹ = 261347 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261859.

It is not an unprimeable number, because it can be changed into a prime (261059) 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, 10059 + ... + 10084.

It is an arithmetic number, because the mean of its divisors is an integer number (70504).

261859 is a Friedman number, since it can be written as 8^6-95*(2+1), using all its digits and the basic arithmetic operations.

2²⁶¹⁸⁵⁹ is an apocalyptic number.

261859 is a deficient number, since it is larger than the sum of its proper divisors (20157).

261859 is a wasteful number, since it uses less digits than its factorization.

261859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20156.

The product of its digits is 4320, while the sum is 31.

The square root of 261859 is about 511.7216039997. The cubic root of 261859 is about 63.9767982304.

The spelling of 261859 in words is "two hundred sixty-one thousand, eight hundred fifty-nine".