25856640 has 144 divisors (see below), whose sum is σ = 90638730. Its totient is φ = 6792192.

The previous prime is 25856629. The next prime is 25856651. The reversal of 25856640 is 4665852.

25856640 is a `hidden beast` number, since 2 + 5 + 8 + 5 + 6 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (25856629) and next prime (25856651).

It can be written as a sum of positive squares in only one way, i.e., 23270976 + 2585664 = 4824^2 + 1608^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 25856595 and 25856604.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 385887 + ... + 385953.

Almost surely, 2^25856640 is an apocalyptic number.

25856640 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 25856640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45319365).

25856640 is an abundant number, since it is smaller than the sum of its proper divisors (64782090).

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

25856640 is an equidigital number, since it uses as much as digits as its factorization.

25856640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 25856640 is about 5084.9424775508. The cubic root of 25856640 is about 295.7041114312.

The spelling of 25856640 in words is "twenty-five million, eight hundred fifty-six thousand, six hundred forty".