25645663656 has 96 divisors (see below), whose sum is σ = 70011021600. Its totient is φ = 8480603520.

The previous prime is 25645663643. The next prime is 25645663661. The reversal of 25645663656 is 65636654652.

25645663656 is a `hidden beast` number, since 25 + 6 + 4 + 566 + 3 + 6 + 56 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6016566 + ... + 6020826.

It is an arithmetic number, because the mean of its divisors is an integer number (729281475).

Almost surely, 2^25645663656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25645663656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35005510800).

25645663656 is an abundant number, since it is smaller than the sum of its proper divisors (44365357944).

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

25645663656 is a wasteful number, since it uses less digits than its factorization.

25645663656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4919 (or 4912 counting only the distinct ones).

The product of its digits is 23328000, while the sum is 54.

The spelling of 25645663656 in words is "twenty-five billion, six hundred forty-five million, six hundred sixty-three thousand, six hundred fifty-six".