25309728 has 36 divisors (see below), whose sum is σ = 71975358. Its totient is φ = 8436480.

The previous prime is 25309723. The next prime is 25309759. The reversal of 25309728 is 82790352.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19607184 + 5702544 = 4428^2 + 2388^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 25309692 and 25309701.

It is not an unprimeable number, because it can be changed into a prime (25309723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 43653 + ... + 44228.

Almost surely, 2^25309728 is an apocalyptic number.

It is an amenable number.

25309728 is an abundant number, since it is smaller than the sum of its proper divisors (46665630).

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

25309728 is a wasteful number, since it uses less digits than its factorization.

25309728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87897 (or 87886 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 25309728 is about 5030.8774582572. The cubic root of 25309728 is about 293.6043546588.

The spelling of 25309728 in words is "twenty-five million, three hundred nine thousand, seven hundred twenty-eight".