25533638550 has 144 divisors (see below), whose sum is σ = 78466034400. Its totient is φ = 5831377920.

The previous prime is 25533638479. The next prime is 25533638551. The reversal of 25533638550 is 5583633552.

25533638550 is a `hidden beast` number, since 2 + 5 + 5 + 3 + 3 + 638 + 5 + 5 + 0 = 666.

It is a super-2 number, since 2×25533638550² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 25533638496 and 25533638505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25533638551) 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, 4876734 + ... + 4881966.

Almost surely, 2^25533638550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25533638550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39233017200).

25533638550 is an abundant number, since it is smaller than the sum of its proper divisors (52932395850).

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

25533638550 is a wasteful number, since it uses less digits than its factorization.

25533638550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6807 (or 6799 counting only the distinct ones).

The product of its (nonzero) digits is 1620000, while the sum is 45.

The spelling of 25533638550 in words is "twenty-five billion, five hundred thirty-three million, six hundred thirty-eight thousand, five hundred fifty".