25805440 has 64 divisors (see below), whose sum is σ = 62797320. Its totient is φ = 10137600.

The previous prime is 25805431. The next prime is 25805443. The reversal of 25805440 is 4450852.

It can be written as a sum of positive squares in 4 ways, for example, as 17372224 + 8433216 = 4168^2 + 2904^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 25805399 and 25805408.

It is not an unprimeable number, because it can be changed into a prime (25805443) 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, 38710 + ... + 39370.

Almost surely, 2^25805440 is an apocalyptic number.

25805440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25805440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31398660).

25805440 is an abundant number, since it is smaller than the sum of its proper divisors (36991880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25805440 is an equidigital number, since it uses as much as digits as its factorization.

25805440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741 (or 729 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 28.

The square root of 25805440 is about 5079.9055109323. The cubic root of 25805440 is about 295.5088030604.

The spelling of 25805440 in words is "twenty-five million, eight hundred five thousand, four hundred forty".