21223473 has 4 divisors (see below), whose sum is σ = 28297968. Its totient is φ = 14148980.

The previous prime is 21223453. The next prime is 21223483. The reversal of 21223473 is 37432212.

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 a cyclic number.

It is not a de Polignac number, because 21223473 - 2⁶ = 21223409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21223403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3537243 + ... + 3537248.

It is an arithmetic number, because the mean of its divisors is an integer number (7074492).

Almost surely, 2^21223473 is an apocalyptic number.

It is an amenable number.

21223473 is a deficient number, since it is larger than the sum of its proper divisors (7074495).

21223473 is an equidigital number, since it uses as much as digits as its factorization.

21223473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7074494.

The product of its digits is 2016, while the sum is 24.

The square root of 21223473 is about 4606.8940730171. The cubic root of 21223473 is about 276.8676095400.

Adding to 21223473 its reverse (37432212), we get a palindrome (58655685).

The spelling of 21223473 in words is "twenty-one million, two hundred twenty-three thousand, four hundred seventy-three".