25805 has 8 divisors (see below), whose sum is σ = 33432. Its totient is φ = 19008.

The previous prime is 25801. The next prime is 25819. The reversal of 25805 is 50852.

25805 = T₅₁ + T₅₂ + ... + T₆₅.

It can be written as a sum of positive squares in 4 ways, for example, as 1156 + 24649 = 34^2 + 157^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25805 - 2² = 25801 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 (25801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134 + ... + 263.

It is an arithmetic number, because the mean of its divisors is an integer number (4179).

2²⁵⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

25805 is a deficient number, since it is larger than the sum of its proper divisors (7627).

25805 is a wasteful number, since it uses less digits than its factorization.

25805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 25805 is about 160.6393476082. The cubic root of 25805 is about 29.5507123510.

The spelling of 25805 in words is "twenty-five thousand, eight hundred five".