25563 has 4 divisors (see below), whose sum is σ = 34088. Its totient is φ = 17040.

The previous prime is 25561. The next prime is 25577. The reversal of 25563 is 36552.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 25563 - 2¹ = 25561 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4258 + ... + 4263.

It is an arithmetic number, because the mean of its divisors is an integer number (8522).

2²⁵⁵⁶³ is an apocalyptic number.

25563 is a deficient number, since it is larger than the sum of its proper divisors (8525).

25563 is an equidigital number, since it uses as much as digits as its factorization.

25563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8524.

The product of its digits is 900, while the sum is 21.

The square root of 25563 is about 159.8843331912. The cubic root of 25563 is about 29.4580462716.

It can be divided in two parts, 2 and 5563, that added together give a triangular number (5565 = T₁₀₅).

The spelling of 25563 in words is "twenty-five thousand, five hundred sixty-three".