25566840 has 160 divisors (see below), whose sum is σ = 92695680. Its totient is φ = 6283008.

The previous prime is 25566839. The next prime is 25566841. The reversal of 25566840 is 4866552.

25566840 is a `hidden beast` number, since 2 + 556 + 68 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (25566839) and next prime (25566841).

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

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 25566795 and 25566804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25566841) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 41817 + ... + 42423.

It is an arithmetic number, because the mean of its divisors is an integer number (579348).

Almost surely, 2^25566840 is an apocalyptic number.

25566840 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 25566840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46347840).

25566840 is an abundant number, since it is smaller than the sum of its proper divisors (67128840).

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

25566840 is a wasteful number, since it uses less digits than its factorization.

25566840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643 (or 630 counting only the distinct ones).

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

The square root of 25566840 is about 5056.3662842005. The cubic root of 25566840 is about 294.5952123197.

The spelling of 25566840 in words is "twenty-five million, five hundred sixty-six thousand, eight hundred forty".