25637640 has 128 divisors (see below), whose sum is σ = 91791360. Its totient is φ = 5601024.

The previous prime is 25637639. The next prime is 25637657. The reversal of 25637640 is 4673652.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18657 + ... + 19983.

It is an arithmetic number, because the mean of its divisors is an integer number (717120).

Almost surely, 2^25637640 is an apocalyptic number.

25637640 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 25637640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45895680).

25637640 is an abundant number, since it is smaller than the sum of its proper divisors (66153720).

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

25637640 is a wasteful number, since it uses less digits than its factorization.

25637640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1371 (or 1367 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 33.

The square root of 25637640 is about 5063.3625191171. The cubic root of 25637640 is about 294.8668938910.

The spelling of 25637640 in words is "twenty-five million, six hundred thirty-seven thousand, six hundred forty".