21225423 has 4 divisors (see below), whose sum is σ = 28300568. Its totient is φ = 14150280.

The previous prime is 21225403. The next prime is 21225431. The reversal of 21225423 is 32452212.

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

It is not a de Polignac number, because 21225423 - 2⁹ = 21224911 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 21225423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3537568 + ... + 3537573.

It is an arithmetic number, because the mean of its divisors is an integer number (7075142).

Almost surely, 2^21225423 is an apocalyptic number.

21225423 is a deficient number, since it is larger than the sum of its proper divisors (7075145).

21225423 is an equidigital number, since it uses as much as digits as its factorization.

21225423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7075144.

The product of its digits is 960, while the sum is 21.

The square root of 21225423 is about 4607.1057074914. The cubic root of 21225423 is about 276.8760887571.

Adding to 21225423 its reverse (32452212), we get a palindrome (53677635).

The spelling of 21225423 in words is "twenty-one million, two hundred twenty-five thousand, four hundred twenty-three".