25391521 has 3 divisors (see below), whose sum is σ = 25396561. Its totient is φ = 25386482.

The previous prime is 25391479. The next prime is 25391533. The reversal of 25391521 is 12519352.

The square root of 25391521 is 5039.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 25391521 - 2⁷ = 25391393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25391521.

It is not an unprimeable number, because it can be changed into a prime (25391551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2520 + ... + 7558.

Almost surely, 2^25391521 is an apocalyptic number.

25391521 is the 5039-th square number.

25391521 is the 2520-th centered octagonal number.

It is an amenable number.

25391521 is a deficient number, since it is larger than the sum of its proper divisors (5040).

25391521 is an frugal number, since it uses more digits than its factorization.

25391521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10078 (or 5039 counting only the distinct ones).

The product of its digits is 2700, while the sum is 28.

The cubic root of 25391521 is about 293.9202932305.

The spelling of 25391521 in words is "twenty-five million, three hundred ninety-one thousand, five hundred twenty-one".