25661279280 has 640 divisors, whose sum is σ = 100793548800. Its totient is φ = 5257654272.

The previous prime is 25661279279. The next prime is 25661279333. The reversal of 25661279280 is 8297216652.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 184613451 + ... + 184613589.

It is an arithmetic number, because the mean of its divisors is an integer number (157489920).

Almost surely, 2^25661279280 is an apocalyptic number.

25661279280 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 25661279280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50396774400).

25661279280 is an abundant number, since it is smaller than the sum of its proper divisors (75132269520).

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

25661279280 is a wasteful number, since it uses less digits than its factorization.

25661279280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361 (or 355 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 48.

The spelling of 25661279280 in words is "twenty-five billion, six hundred sixty-one million, two hundred seventy-nine thousand, two hundred eighty".