21143223 has 12 divisors (see below), whose sum is σ = 32336928. Its totient is φ = 13266240.

The previous prime is 21143207. The next prime is 21143251. The reversal of 21143223 is 32234112.

21143223 is a `hidden beast` number, since 211 + 432 + 23 = 666.

It is not a de Polignac number, because 21143223 - 2⁴ = 21143207 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21143196 and 21143205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143203) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68943 + ... + 69248.

It is an arithmetic number, because the mean of its divisors is an integer number (2694744).

It is a self-describing number.

Almost surely, 2^21143223 is an apocalyptic number.

21143223 is a deficient number, since it is larger than the sum of its proper divisors (11193705).

21143223 is a wasteful number, since it uses less digits than its factorization.

21143223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138214 (or 138211 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21143223 is about 4598.1760514360. The cubic root of 21143223 is about 276.5182056995.

Adding to 21143223 its reverse (32234112), we get a palindrome (53377335).

It can be divided in two parts, 211 and 43223, that added together give a palindrome (43434).

The spelling of 21143223 in words is "twenty-one million, one hundred forty-three thousand, two hundred twenty-three".