25809764640 has 432 divisors, whose sum is σ = 93924702144. Its totient is φ = 5941816320.

The previous prime is 25809764639. The next prime is 25809764641. The reversal of 25809764640 is 4646790852.

It is an interprime number because it is at equal distance from previous prime (25809764639) and next prime (25809764641).

It is a super-2 number, since 2×25809764640² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (25809764641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 185681691 + ... + 185681829.

It is an arithmetic number, because the mean of its divisors is an integer number (217418292).

Almost surely, 2^25809764640 is an apocalyptic number.

25809764640 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 25809764640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46962351072).

25809764640 is an abundant number, since it is smaller than the sum of its proper divisors (68114937504).

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

25809764640 is a wasteful number, since it uses less digits than its factorization.

25809764640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 25809764640 in words is "twenty-five billion, eight hundred nine million, seven hundred sixty-four thousand, six hundred forty".