25516521 has 6 divisors (see below), whose sum is σ = 36857210. Its totient is φ = 17011008.

The previous prime is 25516511. The next prime is 25516537. The reversal of 25516521 is 12561552.

25516521 is a `hidden beast` number, since 2 + 5 + 5 + 1 + 652 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 25401600 + 114921 = 5040^2 + 339^2 .

It is not a de Polignac number, because 25516521 - 2⁵ = 25516489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25516511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1417576 + ... + 1417593.

Almost surely, 2^25516521 is an apocalyptic number.

It is an amenable number.

25516521 is a deficient number, since it is larger than the sum of its proper divisors (11340689).

25516521 is a wasteful number, since it uses less digits than its factorization.

25516521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2835175 (or 2835172 counting only the distinct ones).

The product of its digits is 3000, while the sum is 27.

The square root of 25516521 is about 5051.3880270674. The cubic root of 25516521 is about 294.4018176442.

The spelling of 25516521 in words is "twenty-five million, five hundred sixteen thousand, five hundred twenty-one".