25521 has 8 divisors (see below), whose sum is σ = 34944. Its totient is φ = 16560.

The previous prime is 25471. The next prime is 25523. The reversal of 25521 is 12552.

25521 = T₄₄ + T₄₅ + ... + T₆₁.

25521 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25521 - 2⁶ = 25457 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 25521.

It is not an unprimeable number, because it can be changed into a prime (25523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51 + ... + 231.

It is an arithmetic number, because the mean of its divisors is an integer number (4368).

2²⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

25521 is a deficient number, since it is larger than the sum of its proper divisors (9423).

25521 is a wasteful number, since it uses less digits than its factorization.

25521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231.

The product of its digits is 100, while the sum is 15.

The square root of 25521 is about 159.7529342454. The cubic root of 25521 is about 29.4419042414.

It can be divided in two parts, 255 and 21, that added together give a triangular number (276 = T₂₃).

The spelling of 25521 in words is "twenty-five thousand, five hundred twenty-one".