25521728 has 28 divisors (see below), whose sum is σ = 51107340. Its totient is φ = 12644352.

The previous prime is 25521703. The next prime is 25521733. The reversal of 25521728 is 82712552.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1236544 + 24285184 = 1112^2 + 4928^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 25521694 and 25521703.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5468 + ... + 8996.

Almost surely, 2^25521728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25521728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25553670).

25521728 is an abundant number, since it is smaller than the sum of its proper divisors (25585612).

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

25521728 is a wasteful number, since it uses less digits than its factorization.

25521728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3654 (or 3644 counting only the distinct ones).

The product of its digits is 11200, while the sum is 32.

The square root of 25521728 is about 5051.9034036688. The cubic root of 25521728 is about 294.4218418735.

The spelling of 25521728 in words is "twenty-five million, five hundred twenty-one thousand, seven hundred twenty-eight".