25644840 has 128 divisors (see below), whose sum is σ = 87816960. Its totient is φ = 5935104.

The previous prime is 25644833. The next prime is 25644841. The reversal of 25644840 is 4844652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25644841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26037 + ... + 27003.

It is an arithmetic number, because the mean of its divisors is an integer number (686070).

Almost surely, 2^25644840 is an apocalyptic number.

25644840 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 25644840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43908480).

25644840 is an abundant number, since it is smaller than the sum of its proper divisors (62172120).

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

25644840 is a wasteful number, since it uses less digits than its factorization.

25644840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011 (or 1007 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 33.

The square root of 25644840 is about 5064.0734591828. The cubic root of 25644840 is about 294.8944944934.

The spelling of 25644840 in words is "twenty-five million, six hundred forty-four thousand, eight hundred forty".