25647840 has 120 divisors (see below), whose sum is σ = 90561240. Its totient is φ = 6835968.

The previous prime is 25647821. The next prime is 25647841. The reversal of 25647840 is 4874652.

25647840 is a `hidden beast` number, since 2 + 5 + 647 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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 = 25647795 and 25647804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25647841) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11971 + ... + 13949.

It is an arithmetic number, because the mean of its divisors is an integer number (754677).

Almost surely, 2^25647840 is an apocalyptic number.

25647840 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 25647840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45280620).

25647840 is an abundant number, since it is smaller than the sum of its proper divisors (64913400).

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

25647840 is a wasteful number, since it uses less digits than its factorization.

25647840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2006 (or 1989 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 25647840 is about 5064.3696547547. The cubic root of 25647840 is about 294.9059932197.

It can be divided in two parts, 2564 and 7840, that added together give a square (10404 = 102²).

The spelling of 25647840 in words is "twenty-five million, six hundred forty-seven thousand, eight hundred forty".