25659640 has 16 divisors (see below), whose sum is σ = 57734280. Its totient is φ = 10263840.

The previous prime is 25659637. The next prime is 25659643. The reversal of 25659640 is 4695652.

It is an interprime number because it is at equal distance from previous prime (25659637) and next prime (25659643).

It is a self number, because there is not a number n which added to its sum of digits gives 25659640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25659643) 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, 320706 + ... + 320785.

Almost surely, 2^25659640 is an apocalyptic number.

25659640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25659640 is an abundant number, since it is smaller than the sum of its proper divisors (32074640).

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

25659640 is a wasteful number, since it uses less digits than its factorization.

25659640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 641502 (or 641498 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 25659640 is about 5065.5345226343. The cubic root of 25659640 is about 294.9512128455.

The spelling of 25659640 in words is "twenty-five million, six hundred fifty-nine thousand, six hundred forty".