25261604550 has 324 divisors, whose sum is σ = 85503115620. Its totient is φ = 5329134720.

The previous prime is 25261604549. The next prime is 25261604567. The reversal of 25261604550 is 5540616252.

25261604550 is a `hidden beast` number, since 25 + 26 + 1 + 60 + 4 + 550 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 161 ways as a sum of consecutive naturals, for example, 3723061 + ... + 3729839.

It is an arithmetic number, because the mean of its divisors is an integer number (263898505).

Almost surely, 2^25261604550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25261604550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42751557810).

25261604550 is an abundant number, since it is smaller than the sum of its proper divisors (60241511070).

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

25261604550 is a wasteful number, since it uses less digits than its factorization.

25261604550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6837 (or 6809 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The spelling of 25261604550 in words is "twenty-five billion, two hundred sixty-one million, six hundred four thousand, five hundred fifty".