25566660 has 144 divisors (see below), whose sum is σ = 89945856. Its totient is φ = 5757696.

The previous prime is 25566649. The next prime is 25566677. The reversal of 25566660 is 6666552.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 129682 + ... + 129878.

It is an arithmetic number, because the mean of its divisors is an integer number (624624).

Almost surely, 2^25566660 is an apocalyptic number.

25566660 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 25566660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44972928).

25566660 is an abundant number, since it is smaller than the sum of its proper divisors (64379196).

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

25566660 is a wasteful number, since it uses less digits than its factorization.

25566660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 25566660 is about 5056.3484848258. The cubic root of 25566660 is about 294.5945209650.

It can be divided in two parts, 2556 and 6660, that added together give a square (9216 = 96²).

The spelling of 25566660 in words is "twenty-five million, five hundred sixty-six thousand, six hundred sixty".