25405 has 4 divisors (see below), whose sum is σ = 30492. Its totient is φ = 20320.

The previous prime is 25391. The next prime is 25409. The reversal of 25405 is 50452.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6084 + 19321 = 78^2 + 139^2 .

It is not a de Polignac number, because 25405 - 2⁵ = 25373 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25409) 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, 2536 + ... + 2545.

It is an arithmetic number, because the mean of its divisors is an integer number (7623).

2²⁵⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

25405 is a deficient number, since it is larger than the sum of its proper divisors (5087).

25405 is an equidigital number, since it uses as much as digits as its factorization.

25405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5086.

The product of its (nonzero) digits is 200, while the sum is 16.

The square root of 25405 is about 159.3894601283. The cubic root of 25405 is about 29.3972292883.

Adding to 25405 its reverse (50452), we get a palindrome (75857).

The spelling of 25405 in words is "twenty-five thousand, four hundred five".