25421 has 4 divisors (see below), whose sum is σ = 27744. Its totient is φ = 23100.

The previous prime is 25411. The next prime is 25423. The reversal of 25421 is 12452.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 25421 - 2⁶ = 25357 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25396 and 25405.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 25421.

It is not an unprimeable number, because it can be changed into a prime (25423) 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, 1145 + ... + 1166.

It is an arithmetic number, because the mean of its divisors is an integer number (6936).

2²⁵⁴²¹ is an apocalyptic number.

It is an amenable number.

25421 is a deficient number, since it is larger than the sum of its proper divisors (2323).

25421 is a wasteful number, since it uses less digits than its factorization.

25421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2322.

The product of its digits is 80, while the sum is 14.

The square root of 25421 is about 159.4396437527. The cubic root of 25421 is about 29.4033994249.

Adding to 25421 its reverse (12452), we get a palindrome (37873).

The spelling of 25421 in words is "twenty-five thousand, four hundred twenty-one".