21443123 has 8 divisors (see below), whose sum is σ = 23656416. Its totient is φ = 19310400.

The previous prime is 21443119. The next prime is 21443129. The reversal of 21443123 is 32134412.

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

It is a cyclic number.

It is not a de Polignac number, because 21443123 - 2² = 21443119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21443095 and 21443104.

It is not an unprimeable number, because it can be changed into a prime (21443129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19583 + ... + 20648.

It is an arithmetic number, because the mean of its divisors is an integer number (2957052).

Almost surely, 2^21443123 is an apocalyptic number.

21443123 is a deficient number, since it is larger than the sum of its proper divisors (2213293).

21443123 is a wasteful number, since it uses less digits than its factorization.

21443123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40285.

The product of its digits is 576, while the sum is 20.

The square root of 21443123 is about 4630.6719814731. The cubic root of 21443123 is about 277.8194702871.

Adding to 21443123 its reverse (32134412), we get a palindrome (53577535).

The spelling of 21443123 in words is "twenty-one million, four hundred forty-three thousand, one hundred twenty-three".