22421 has 4 divisors (see below), whose sum is σ = 25632. Its totient is φ = 19212.

The previous prime is 22409. The next prime is 22433. The reversal of 22421 is 12422.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12422 = 2 ⋅6211.

It is an interprime number because it is at equal distance from previous prime (22409) and next prime (22433).

It is a cyclic number.

It is not a de Polignac number, because 22421 - 2¹⁰ = 21397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22441) 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, 1595 + ... + 1608.

It is an arithmetic number, because the mean of its divisors is an integer number (6408).

2²²⁴²¹ is an apocalyptic number.

It is an amenable number.

22421 is a deficient number, since it is larger than the sum of its proper divisors (3211).

22421 is an equidigital number, since it uses as much as digits as its factorization.

22421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3210.

The product of its digits is 32, while the sum is 11.

The square root of 22421 is about 149.7364351118. The cubic root of 22421 is about 28.1980013003.

Adding to 22421 its reverse (12422), we get a palindrome (34843).

Subtracting from 22421 its reverse (12422), we obtain a palindrome (9999).

The spelling of 22421 in words is "twenty-two thousand, four hundred twenty-one", and thus it is an iban number.