25661224008 has 128 divisors (see below), whose sum is σ = 81952819200. Its totient is φ = 7287803712.

The previous prime is 25661223979. The next prime is 25661224049. The reversal of 25661224008 is 80042216652.

It is a happy number.

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 (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 201691 + ... + 303317.

It is an arithmetic number, because the mean of its divisors is an integer number (640256400).

Almost surely, 2^25661224008 is an apocalyptic number.

25661224008 is a gapful number since it is divisible by the number (28) 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 25661224008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40976409600).

25661224008 is an abundant number, since it is smaller than the sum of its proper divisors (56291595192).

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

25661224008 is a wasteful number, since it uses less digits than its factorization.

25661224008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101816 (or 101806 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 25661224008 in words is "twenty-five billion, six hundred sixty-one million, two hundred twenty-four thousand, eight".