25021646656 has 56 divisors (see below), whose sum is σ = 52618005000. Its totient is φ = 11764826112.

The previous prime is 25021646647. The next prime is 25021646717. The reversal of 25021646656 is 65664612052.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3290169600 + 21731477056 = 57360^2 + 147416^2 .

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1349706 + ... + 1368118.

Almost surely, 2^25021646656 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 25021646656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26309002500).

25021646656 is an abundant number, since it is smaller than the sum of its proper divisors (27596358344).

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

25021646656 is a wasteful number, since it uses less digits than its factorization.

25021646656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19691 (or 19681 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 25021646656 in words is "twenty-five billion, twenty-one million, six hundred forty-six thousand, six hundred fifty-six".