25861 has 4 divisors (see below), whose sum is σ = 28224.
Its totient is φ = 23500.
The previous prime is 25849. The next prime is 25867. The reversal of 25861 is 16852.
Subtracting from 25861 its reverse (16852), we obtain a palindrome (9009).
25861 = T63 + T64 + ... +
It is a happy number.
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.
It is a cyclic number.
It is not a de Polignac number, because 25861 - 27 = 25733 is a prime.
It is a Duffinian number.
25861 is a lucky number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (25867) 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, 1165 + ... + 1186.
It is an arithmetic number, because the mean of its divisors is an integer number (7056).
225861 is an apocalyptic number.
It is an amenable number.
25861 is a deficient number, since it is larger than the sum of its proper divisors (2363).
25861 is a wasteful number, since it uses less digits than its factorization.
25861 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2362.
The product of its digits is 480, while the sum is 22.
The square root of 25861 is about 160.8135566425.
The cubic root of 25861 is about 29.5720731243.
The spelling of 25861 in words is "twenty-five thousand, eight hundred sixty-one".