21573223 has 8 divisors (see below), whose sum is σ = 24690848. Its totient is φ = 18464544.

The previous prime is 21573203. The next prime is 21573239. The reversal of 21573223 is 32237512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21573223 - 2⁵ = 21573191 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4165 + ... + 7777.

It is an arithmetic number, because the mean of its divisors is an integer number (3086356).

Almost surely, 2^21573223 is an apocalyptic number.

21573223 is a deficient number, since it is larger than the sum of its proper divisors (3117625).

21573223 is an equidigital number, since it uses as much as digits as its factorization.

21573223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4473.

The product of its digits is 2520, while the sum is 25.

The square root of 21573223 is about 4644.6983755676. The cubic root of 21573223 is about 278.3802011108.

The spelling of 21573223 in words is "twenty-one million, five hundred seventy-three thousand, two hundred twenty-three".